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PART 1
Know all about your AK!!!
With millions of AK rifles and its variants in use all around the world ,it would not be wrong to say that AK has been able to make its own distinct mark in the world of weapons .It has been transformed into an iconic and a cult figure.
If there are many who devout AK then there are also fair share of people who detest it.Yes,there are rifle which are far more accurate ,have better ergonomics ,are lighter and have much less recoil than an AK.Still no one can deny that the AK is the most successful assault rifle in human history. In terms of the number of guns produced, duration of service, and worldwide deployment, it has no equal.
The success of the AK can be mainly attributed to its reliability ,low cost of production ,ease of mass production ,simplicity to operate with minimal working parts.
The name AK-47 is derived from the Russian words “Avtomat Kalashnikova”,here avtomat stands for automatic in russian and Kalashnikova is used in honour of its its principal designer, Mikhail Kalashnikov.The 47 represent the year 1947 ,when this rifle was first tested by the Russian Army.It is a popular theory that AK is the direct copy of german STG-44 rifle (Sturmgewehr 44/storm rifle),we are not going to dwell over it today ,as the crux of this post is to discuss the practical use of this rifle .We will make a post some other day on the history ,controversies ,development and various other variants of this rifle.
Before we start, we would like to request you to refer to the photo we have posted below to make yourself familiar to the various parts of this rifle,this will help you to understand the post ,in a much better way.We would also like to point out that the designation AK-47 is often used, generically,to refer to all Kalashnikov-pattern assault rifles.However, the AK-47 is a specific model of Kalashnikov. There have been many variants of this rifles and there have been many other rifles that have been produced based on it,however today we are going to discuss it in context of AKM specifically,as it is the most widely used variant in our country.AKM is a redesigned and improved version of the AK-47,here M stands for modernized or upgraded AK .It was introduced in 1959.The improvement on AKM over original AK 47 were that it was made with stamped sheet metal receiver, instead of the receiver of the AK-47 that was machined from a solid steel billet ,thus bringing down the cost of production as well as a reduction in the weight of the rifle.It also featured a slanted compensator at the muzzle end of the barrel to reduce muzzle rise under recoil.
Today,we will not only learn about the basic structure ,parts of an AKM but we will also learn how to live with an AK.Before we proceed any further make yourself familiar with the various parts in an AKM.
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General overview of AKM parts-
In the front end of the rifle ,at the mouth of the barrel there is a slant muzzle compensator(half cut from top at the front of the barrel of the rifle )(a compensator is a device that prevent the rifle from jumping up during firing),as you can see in the design the compensator is cut from top portion,it is to direct all the expanding hot gases towards upward direction of the muzzle of the barrel.The upward escaping gas push the muzzle downward(every action has an equal and opposite reaction) this downward force counter the jump of the rifle due to recoil and keep the rifle stable for quick follow up shots.This slanted compensator is generally screwed into the thread present in front end of the barrel,where you can mount a muzzle device of your choice,but sometimes this compensator could also be welded to barrel,in such case it can't be removed from the barrel.Beside compensator there are two other type of major muzzle device which can be used in an ak. First is muzzle brake ( a muzzle brake is a device that redirects all the escaping gases from a the muzzle towards rear of the rifle,thus pushing the rifle towards front ,this force toward the front counter the recoil force toward the rear of the rifle and thus counterbalance it .So basically muzzle brake are used to reduce the recoil of a rifle) .Second type of muzzle device is a Flash hider (as the name suggest it used in rifle to reduce the flash at the muzzle end of the rifle.When a bullet exist from the muzzle of the rifle,the gases generated by it have many particles that burn and produce bright flash,the flash hider disperse these gases in such a way that those particles are dispersed all over thus reducing the flash that is created by the burning of those particles.This diminishes distracting, blinding light experienced by the shooter in darker surroundings due to the flash of the rifle.).In the original AKM you will see the slant muzzle compensator which direct some of the gases coming out of the muzzle upwards and right,as a result it significantly reduces muzzle climb and rightward muzzle drift during very rapid fire but in later model and custom AKM you can see various design of muzzle brake and flash hider mounted on them,as per the user choice.
Just behind the muzzle device is the barrel of the rifle(basically a metal tube through which the bullet is fired).This barrel is 436mm in length(the length is upto the muzzle).It is a rifled barrel with four right-hand grooves (A rifled barrel is the one in which spiral grooves are cut inside a gun barrel, that give the bullet a spinning motion,which makes it stable during flight),those barrel which does not have any rifling or spiral grooves are called smooth bore barrel.The twist rate of the barrel is 1 in 9.45 ( twist rate refers to the rate of spin of the bullet in the rifle barrel before it comes out of it, twist rate is represented in inches per turn.For eg with twist rate of 1:9.45 the bullet will spin one revolution in 9.45inches inside the barrel,twist rate is determined by the number of spiral grooves cut inside the barrel which spin the bullet as it travel out.It’s important that your barrel has an adequate twist rate to stabilize the bullet,the ideal twist rate depend on the size of the bullet and the barrel,AKM has adequate twist rate for a 7.62x39mm bullet.)
At the rear end of this barrel ,located inside the rifle is chamber,a chamber is the portion of the barrel that holds the round, ready for firing.The chamber is especially designed and reinforced to withstand the pressure and blast from explosion of the bullet primer that propel the bullet forward,it is because of the chamber that your rifle does not explode ,despite of the mini explosion inside it,every time your fire a bullet.
-Next just behind the muzzle of the barrel there is a fixed iron sight,which is of post type,this post resemble a vertical straight line in shape .The front sight consist of a base which is held tightly to the barrel by means of pins.The front sight post is screwed at the top centre of this base,the sight post is threaded and screws into a floating cylinder that is used for windage adjustments during sighting.The front sight base also has two protecting ears(two semi circles ) on top of it covering the front sight post form both sides,these ears protect the front sight post from any disturbance from outside factors,they are integrated part of the sight block.The front sight post is covered from both the sides by these ears and at rear from the sight base to protect it,however it is left exposed from top to allow the sight adjustment tool to reach it(basically to rotate the post to adjust for elevation).The round section at the upper section of the front sight block(above the cut out area) is the foresight stud/windage drum,this can be moved left or right to adjust windage for zero.You should always remember that you can adjust your bullet impact by moving the front sight post in the opposite direction you want your bullet impact to move.For example if you want your bullet impact to go up you will have to screw in /down the front sight post ,if you want the bullet impact to go down you will have to screw out/up the front sight post.Similarly when you want the bullet impact to go towards left you will have to push the front sight post towards right,whereas when you want the bullet impact to go towards right you will have to push your front sight post towards left.You can adjust the front sight post towards left or right through the windage drum present just below the ears of the front sight post(round shape beneath the ears)It can be done using an empty cartridge and a hammer.When you are zeroing your rifle (that is your point of aim should be equal to the point of impact of the bullet at the given distance )you can adjust your front sight post for it,by moving it in the opposite direction.Basically if you want to shift the point of impact(POI) of the bullet to right,you shift the front sight post to left,if you want (POI) to move to right ,you move the front sight post to right.Similarly if you want (POI) to move down,you screw the front sight post up,if you want (POI) to go up ,you screw the front sight post down.Please note that front sight post is attached to the base of front sight by screwing it in the threaded portion in the centre meant for it.There are two circular drum on both outer side of the front sight block called windage drum,it is through them that we push the front sight post left or right.You can use an empty cartridge and a hammer to move the front sight post left or right by keeping one end of the cartridge on the windage drum and hitting it with the hammer toward the opposite direction you want your bullet impact to move.The front sight block also has a recess at its bottom ,which holds the cleaning rod head.
- Just below the barrel is a cleaning rod ,a thin metal rod used for cleaning the barrel and for checking and clearing any obstruction in the barrel.The cleaning rod head is held by a recces/a hollow space at the base of front sight block,then it goes through a hole at the base of the gas block(again situated on the barrel) and goes into a hole in the handguard retainer.The cleaning rod is held in its place by the tension between the gas block and the front sight block.
- Just after the front sight block there is a hollow metal tube going up at an 45 degree angle from the rifle barrel and then connecting the barrel with a cylindrical tube present at the the top of the barrel .This metal block connecting the rifle barrel to the cylinder is called a gas block.The basic purpose of this gas block is to divert the gases from the barrel to the cylinder above,these gases are the driving force behind the AKM operating cycle.There is a small hole drilled at the top of the barrel,this hole is drilled at 45 degree angle(now many AK have this hole drilled at 90 degree angle) ,this hole is called gas port.The purpose of the gas port is to direct the escaping gases towards the rifle gas tube ;to help in cycling the bolt carrier.Gas block is a hollow metal tube which connect this gas port with the gas tube situated above the barrel.It will be slanted at 45 degree angle to offer the escaping gas a path of least resistance as they travel from a 45 degree gas port on the barrel through the gas block towards the rear of the rifle.The gas block fits on the barrel very tightly and is locked by two pins.At the base of the gas block below the barrel is a notch/hole ,through which the cleaning rod passes.At the top the gas block has circular edge through which it is connected to the gas tube.The gas block also has few small semi circular vent holes in the side edge of its top circular end which connects to the gas tube/gas cylinder.The purpose of these holes is to vent out all the excess and foul gases and carbon out ,as once the gas has pushed the gas piston in it's rearward movement,the gas has no more job. The holes vent our the gas after the piston starts moving.(Piston head is seated in the upper circular portion of the gas block,piston head is pushed back by the pressure of the gas which travel upwards from the barrel through the gas block ,and once it meets a resistance in form of piston head,it applies it force on it thus pushing it backward,as the piston move backward it exposes the holes present in the edges of the gas block , providing a escape route to the gases.As,Once the gas piston exits the gas block the pressure is no longer needed, enough momentum has been imparted to the carrier that it continues rearward on it's own. At this point the gas exits the holes to keep the hot gases from following the tube and releasing them into the receiver.)
- Attached to the upper circular end of the gas block,just behind it is the gas tube.The gas tube is a hollow metal tube ,cylindrical in shape .Front end of the gas tube is attached to the rear end of the gas block by just inserting the some part of the front end of gas tube into the rear circular end of the gas block.Whereas at the rear end of the gas tube there is an indent which is seated inside the space in the rear sight block ,where the gas tube is locked by turning the gas tube retaining lever down at an 45 degree angle.This lever is at the right hand side of the rear sight block .The gas tube itself just acts as a guide for the gas piston,which runs through inside of the gas tube .When the piston is not cycling ,it sits inside the gas tube ,with the piston head at the rear end of the gas block.The gas tube is fluted so some of the gas flows around the piston once it's out of the gas block,to reduce friction.The upper handguard of the rifle is clamped to the top of the gas tube.Only some portion of the gas tube is visible from outside ,attached to the gas block,rest of the portion is covered by the handguard,the gas tube go till the front end of the rear sight block.Two metal ring which resemble the "u" shape are fastened on the rear end and near the front end of the gas tube,these ring are fastened on the gas tube in inverted position,on top of the gas tube will come the top part of inverted "u" ,please do note reference to "u" is to just give some idea of shape.These ring are used to clamp the upper handguard to the gas tube ,these ring are known as front and rear joining collars/handguard retainers of the gas tube.
- When you are viewing the AK from outside ,after the gas tube what you will see on the rifle is handguard.Handguard as the name suggest is to protect the shooters hand from burning form heat generated in the barrel ,as well as for the convenience of gripping the rifle.The handguard are made up of laminated wood.The handguard is divided into two parts,upper and lower as the name suggest upper handguard cover the top of the rifle .It is mounted on the gas tube ,for mounting the upper handguard on the gas tube ,first Using a wrench , gently lock across the flat side portions in back of the gas tube(this is the same portion of the gas tube that seats in the rear sight block),Now with the upper handguard upside down place it at the bottom of the gas tube and push up the handguard into the gas tube,once the hand guard sits on the gas tube,rotate the handguard with gas tube held at its position through wrench.(Remember the handguard is upside down,so basically it sits inverted on the gas tube ,when you will successfully rotate the handguard ,it will return to its original position ,and will sits on the gas tube with the upside of the handguard on top,by doing this you will basically lock the handguard on the gas tube.The upper handguard has 4 recesses/cut out portion at its bottom end ,two on each side.These are there for air circulation to assist in cooling of the barrel,as the barrel tend to heat up from sustained firing of bullets from it.(these are basically cut at the bottom of the handguard which make space,opening,vent for the airflow,so as to vent out the heat of the barrel easily).There is a metal pressure clip seated inside the handguard,this help the handguard to clamp on the gas tube.As the handguard is already attached to the gas tube ,we do not need to retain the handguard on the rifle,it is retained along with the gas tube ,which is installed with its forward end in the gas block and its rear end in the notch of the rear sight base and is locked by means of a gas tube retaining lever present on the rear sight block.
-Similar to the upper handguard the lower handguard is also made up of laminated wood.The lower handguard is also known as fore-end .It is large at the rear and tapers(narrow down) at the front.It has got 4 recesses(vents cut out ),two at each side at its bottom.There is a horizontal bulge at its centre on both side,it is there to aid in gripping the rifle.There is also a thin U shaped metal clamp inside the handguard ,which protects the handguard from wrapping or sticking to the barrel.The lower handguard is installed on the barrel of the rifle ,upside down.For installing lower handguard there is a handguard retainer ring,which is a metal ring ,that is mounted on the barrel of the rifle,this handguard retainer ring has a small hole at its bottom,through which the cleaning rod passes.It also has a side ring which is used to mount the sling of the rifle.This retainer ring can be slided forward and back on the barrel.When you have to install the lower handguard just slide this retainer ring to the front of the barrel ,near the gas block.Now push up the lower handguard upside down ,on the barrel.At the back of the wooden handguard there will be a wooden tab protruding out,slide this wooden tab in the opening at the front of the receiver ,below the barrel.Through this you will be attaching the rear of the handguard to the front of the rifle receiver .Now slide back the handguard retainer ring present on the barrel (which you have slided forward a while ago)When the retainer ring reaches the front end of the handguard .Now there will be a small lever ,which will be facing towards the muzzle of the rifle,push this lever at 180 degree angle ,inside the lower handguard pointing towards the rear of the rifle and in line with the barrel of the rifle.Once this lever is pushed towards the handguard side,the retainer ring will lock the handguard in its place.
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-Please do note that later on the russian themselves ,as well as the others in the world moved away from the wooden handguard ,to polymer handguards for the AKM.
-Right after the front handguard , the rear sight block of the AKM is located at the top of the rifle.It is a rear "U" notched type open iron sight ,with elevation for different ranges.The rear sight block consist of a base and a sight leaf at the top of the base.The sight leaf is mounted on a ramp ,which is part of the base.The sight base has a lug/hole,by means of which the sight is mounted on the barrel with help of a pin,which hold the base on the barrel.A gas tube lock lever is located out,on the right hand side of the base .Turning this lever to 45 degree down locks the rear of the gas tube into the base,whereas turning this lever up will release the gas tube from the base.The sectors or the ramp is integral with the top of the sight base and is used to set the desired ranges.The sight leaf have markings for shooting at different distances measured in meters.The adjustments are intended to change the ballistic trajectory so that point of aim and point of impact are the same at the respective distance selected on the sight.The sight leaf has odd numbers inscribed on the right side from 1 to 9 ,which represent the ranges of 100 to 900 meters .On the left side there are inscribed even numbers from 2 to 10,which correspond to ranges of 200 to 1000 meters.On the left side of the sight leaf is the letter "p"(Symbol could be different depending on the country of origin).It is located at the rear most position on the sight leaf below the number 1.The rear sight leaf has a sight bar with rectangular notches for the catch teeth ,longitudinal notch for the exact indexing of the inscribed number .
-The metal body right behind the lower handguard is the receiver of the AKM,before we dwell further regarding the details of the receiver on the AKM ,let's first understand the concept of receiver.A receiver is a frame or that part of rifle which house the breech block, bolt and the firing mechanism of the rifle.In AKM and most of the rifles receiver is usually single body housing all the components named above ,however in some rifle like the m16,ar 15 design the receiver is divided into 2 parts instead of one single body.The receiver in an ar 15 rifle is divided into upper and lower ,where the top part is housing the barrel and bolt while the lower part is housing the trigger group, the two parts are held together by a pin ,by disengaging the pin you can separate the two.
Now returning back to the AKM ,the receiver of the AKM is made from the stamped sheet steel, with machined steel inserts riveted into the place where required.In a stamped receiver a flat piece of thin metal sheet is stamped and bent into a box shape and riveted with a center spacer with both front and rear trunnions.The other type of receiver commonly found in rifles is machined/milled receiver ,here each receiver is machined from a block of steel into shape rather than stamping various sheet of steel into a particular shape. All the internal guide rails, magazine well and latch surfaces, bolt locking surfaces, bolt carrier stop, and the barrel and buttstock receiving sockets, were cut into the same, single piece of steel.We will talk about the differences among these two receiver some other day.
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However ,since we are talking about the stamped and machined receiver you must be wondering how you can differentiate between the two.There are two ways to visually differentiate between a machined and a stamped receiver
1 .A machined receiver has a large horizontal rectangular shaped cut-out , which is nearly 5 inches long on each side of the receiver, above the magazine slot ,at the lower edge of the receiver. It was designed to reduce the overall weight of the rifle.Just look above the portion where you have inserted the magazine of the rifle.Whereas in a stamped receiver at the same position on each side of the receiver ,instead of a rectangular cutout we have a small, shallow indentation,about 1-inch long .You can see a smaller, more rounded dimple just above where the magazine is inserted this dimple is known as "magazine guide".
Please note that the purpose of the dimple in the stamped receiver and the rectangular cut in the machined receiver is totally different .The dimple is there to act as the magazine guide,it act as the indicator of the centre point of the magazine ,when the magazine is inserted into the receiver.Whereas the rectangular slot in the machined receiver is done to reduce the weight of the receiver by slicing off some metal,also do remember that both the dimple and the rectangular slot are on both side of the receiver at corresponding positions.
2. Other method for differentiating between the two receiver is to check the rear of both the receiver by removing the rifle stock.The design of the rear side of both the receiver is different .Where is stamped you a a open rectangular opening in a machined receiver you have a narrow inverted "U" shaped opening(please refer to the photo).Due to this difference is design the stock of a stamped receiver AKM cannot be mounted on a machined receiver AKM and vice -versa.
While we are at it,let's learn the brief history of AK receiver.The soviet experimented with 4 different receivers (including the present stamped one) before they settled for the stamped receiver which you see in the AKM,which is the 4th and final receiver .The first receiver of Ak rifle was made from a sheet steel stamping fitted with a machined steel trunnion into which the breech of the barrel was fitted.But there were problem in welding the internal component to this type of receiver ,the heat generated from the welding used to cause the receiver to bent making it unsuitable.As a result of this a second method of production was used to manufacture the receiver ,that was machined receiver -the method of maching the receiver from a solid block of steel.The machined receiver ,which will be the 2nd type was heavier but stronger than the stamped receiver and had rectified the problem of bending due to heat faced in the previous (1st) receiver.However a new problem cropped up in this type of receiver .The fitting of existing stock was having difficulty in this type of receiver ,that led to redesigning of this receiver .The 3rd receiver was also a machined one but it differed from the 2nd receiver mainly in the method of fixing the stock to the receiver.Although the machined receiver were working fine ,they were complex,expensive to produce and were heavy ,which led to the designers to continue to find the solution of the problem faced in the 1st type stamped receiver.With the help of simple changes to the design and production methods and with the help of various german engineer working in Russia ,they were able to eventually overcome the problems they faced with stamped receiver.Some of the changes were less use of welding and more use of riveting and stamped parts.These improvement resulted in the type of 4 stamped receiver,and a new weapon designation -the Avtomat Kalashnikova Modernizirovanniy or AKM.The type 4 receiver first appeared during 1955,but it was not until 1959 that the design had been sufficiently developed for it to be accepted into service as the standard weapon type.
Now coming back to the stamped AKM receiver which we are discussing.The Russian AKM receiver is stamped from a flat sheet of thin metal, bent into its "U" box shape, and riveted together with a center spacer and both a front and rear trunnion(A trunnion is something which is used as a mounting and pivoting point). Instead of being pinned or threaded directly into the receiver as in a milled receiver, the barrel for a stamped AK is pinned into a barrel trunion,located at the front of the receiver. The front trunnion contains the bolt locking and carrier stop surfaces. The trunnion is then riveted into the front of the receiver. Similarly, a rear trunnion is riveted into the back of the receiver and forms the buttstock socket, stock tang, and the carrier return spring mounting slot.
On the exterior of the receiver,at left side in the front,just behind the top portion of the rear of the lower handguard, there is the serial number of the rifle ,year of manufacture and factory marking of the rifle.The three protruding rivet heads which can be seen at the front of the receiver are the rivets that are holding the front trunnion inside the receiver ,similarly two rivet head can be seen at the rear end of the receiver which are holding the rear trunnion inside the receiver.These rivets can also be seen from the right hand side of the receiver ,as these are the rivet points of the front and rear trunnion.The circular weld marks for the internal bolt guide are also clearly visible on the side of the receiver.There is also a small depression or dimple just above the magazine slot of the receiver ,this act as a magazine guide .There are two dimple at corresponding to each other on both sides of the receiver ,these dimples act as the magazine guide that keep the magazine centered in the rifle.
On the right side of the AKM receiver ,just above the pistol grip you can see the selector lever of the AKM ,this selector lever has added central reinforcing rib,the selector lever as the name suggest is used to select firing mode of the rifle.Just above the rear end of the magazine slot ,there are markings that are stamped on the receiver ,these marking indicate the firing mode for the selector lever.Always remember the topmost position is for safe,middle position of the lever is for automatic/burst and the bottom position is for single shot in AKM and please note there is no marking for safe position you must know that topmost position is for safe,rest there are marking at middle and bottom for automatic and single shot respectively.The receiver also has a selector stop to prevent the selector lever being force down too far.It is positioned above the forward edge of the trigger guard.
At the front top edge of the receiver ,there is a metal tab protruding out of the receiver ,this is called charging/cocking handle,It is permanently attached to the bolt carrier(we will talk about it after this) and reciprocates(move rearward and forward) when the rifle is fired.Just above the position where charging handle is placed when at rest, is the ejection port,it is a 45 degree angle slot which ejects out the spent casing of the bullet when the bolt carrier move rearward.When the rifle is not firing this ejection port is covered by the bolt carrier ,it is exposed only when the bolt carrier move backward ,either on its own or either by manually pushing back the bolt carrier through the charging handle that is protruding out.
On top of the receiver is the top cover also known as dust cover/receiver cover ,as the name suggest it is a cover for the receiver .The top cover is there to protect the receiver from outside elements and preventing dust from going in the receiver.The top cover is made up thinner sheet metal than the one used for the receiver,hence to strengthen the top cover a series of ribs have been stamped on the top cover(the rib pattern on the top cover can be clearly seen,these are for strengthening the top cover).This top cover has a rectangular slot at its rear ,through which the recoil spring guide lug passes and locks the top cover to the rifle.The top cover is fastened to the receiver by its forward face,which enters a semicircular groove in the base of the rear sight,and by means of the lug of the return spring guide rear end,which enters the opening in the rear wall of the receiver cover.The top cover is designed in such a way ,that when it is seated over the receiver ,it leaves a slot in the front half area between it and the receiver,this area is left to aid the rearward movement of the bolt carrier and the charging handle protruding out of it as well as for the ejection port.
Inside the receiver there is a rigid tubular cross-section support that adds structural strength to the receiver.At top end of the inside of the receiver there are two rails ,one on each side facing each other ,these are known as top rails.Just below the top rails at some gap are two guide rails ,one on each side.The purpose of these rails is to aid in sliding of the bolt carrier group .The left hand side guide rail(which is below the top rail ) has a shark fin type indent protruding out,this is known as ejector as the empty casing are pushed outside the rifle by it as they are moving backward along with the bolt carrier group.(To understand the design of the top rail and the guide rail please refer to the photo )
At the rear end of the receiver there is a slot ,through which the butstock of the rifle is attached to the rear trunnion.At the bottom of the receiver there are three slot,front one for magazine slot,middle one for trigger and the rear one for the pistol grip.
Talking about the main component which are housed inside the receiver;first and foremost we will talk about the bolt carrier group.Bolt carrier group has the operating rod ,which is the main body of the bolt carrier ,to the operating rod at the front piston rod is attached,whereas the bolt sits in a cylindrical body at the bottom of the operating rod.This is known as bolt carrier group.
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The bolt carrier group comprise of bolt carrier ,piston and bolt
Bolt carrier-
Bolt carrier has a hollow rod at the top known as the operating rod,a piston rod is attached at the front of the operating rod by means of threads and pin which is installed in a hole present in the forward end of the operating rod.
The bolt carrier has a has a cylindrical channel at its rear end in which the rear end of the bolt is installed.In the sides of the bolt carrier there are grooves which guides the operating rod in the receiver by riding on the guide rails present in the receiver.On the right side there is a lug which disconnects the automatic sear and is called the full automatic disconnector.On the left side there is a notch for passing the ejector.Bolt carrier also have a rear bevel for smooth cocking of the hammer when the operating rod is moving to the rear and a forward bevel for depressing the cocked hammer as the operating rod is moving forward.
On the right side of the bolt carrier there is a charging handle integrated to it.
In the central portion of the bolt carrier there is a cam surface on which the bolt guide lug rides.The bolt rotates due to its the movement of its guide lug on this cam surface.This cam surface act as railway track and the lug on the bolt act as the wheel of a train which are set on the tracks.As the bolt carrier move forward or rear- ward the tracks passes through the guide lug on the bolt causing the rotation of the bolt.
Bolt -
The bolt consist of a body,firing pin,spring loaded extractor and two retaining pin-one for firing pin and other for extractor.
The bolt head(front portion of the bolt) has a right and left lugs ,which locks with the receiver lugs when the bolt rotates clockwise.It has a guide lug ,which when travel through the cam track machined in the bolt carrier causes the bolt to rotate.Then the bolt head also have a forward edge ,which pushes out the top most round from the magazine and feed it into the chamber ,through a ramp.
The bolt also have extractor (a metal claw) in ihe front face of the bolt.The extractor which is spring loaded grasp the rim of the cartridge as it is pushed inside the chamber ,when a round is fired the extractor pull out the cartridge from the chamber.The extractor with spring is installed in the bolt in the bolt head by means of pin.In the bolt body there is a longitudinal groove for passing the extractor,in the rear portion the groove is made wider for passing the extractor when the bolt is rotating as the chamber is being sealed or opened.
In the center of the body there is a channel for housing the firing pin.In the forward position the channel is conical in shape,and the other end terminates in a hole for passing the tip of the firing pin.The firing pin when struck by the hammer at rear ,pierces the primer of the cartridge setting it off.
The firing pin is divided into the rear and the forward portion .The portion terminates in the tip of the firing pin1,in the rear portion there are three longitudinal grooves for decreasing the weight of the firing pin and for decreasing friction as it moves in the channel in the bolt body.The firing pin is prevented from falling out of the bol body by a retaining pin,which passes a notch in the firing pin.
Piston -
To the operating rod of the bolt carrier the piston rod is attached at the front top portion by means of threads and pin which is installed in hole in a hole present in the forward end of the operating rod.A piston in simple terms is a metal rod with a head which is attached to he operating rod and form a part of the bolt carrier.Piston head receives the pressure of the gases in the gas block and start moving rearward,the piston rod transfer this momentum to the operating rod which also start moving rearward resulting in whole bolt carrier moving back(bolt carrier group = bolt carrier+piston+bolt)
On the forward face of the piston there is a sharp rim which scrapes off carbon from the walls of the gas cylinder as the operating rod moves.
Charging handle -
The charging handle is a metal tab present at the right top hand of the bolt carrier and protruding out from the right side of the receiver.It is called charging/cocking handle because by pulling it to the rear and then releasing it ,by which it return back to the front you charge,cock the rifle that is cock the hammer and chamber a round if there is one in the magazine.This process is called charging or cocking the rifle.
When the escaping gases hit the piston head seated in the gas block,it is pushed backward ,when the piston rod travel backward,the whole bolt carrier group travel backwards in the receiver ,as the bolt carrier group travel backwards, it cocks the hammer ,when it reaches the rear of the receiver it is pushed forward by the recoil spring connected at the rear channel present in the bolt carrier group .So this is how the bolt carrier group move inside the receiver when rifle is fired.
The return mechanism inside the receiver consist of return spring,guide ,guide rod .The return spring as the name suggest is a spring which is placed horizontally at the rear of the receiver ,its head is placed inside the channel,present at the top rear edge of the bolt carrier group.It is connected to the bolt carrier group through it.The return spring return the bolt carrier to the extreme forward position after firing.The guide and the guide rod are metal rods on which the return spring ride during its movement ,these rod prevent the return spring from bending and help in keeping it straight.Guide rod is at the front of the return spring and the guide at the rear portion ,the return spring is placed over these rods.On the inside forward portion of the guide there is a shoulder which stops the guide rod ,when the return spring travel rearwards.The guide also has a lug at its rear ,through which the return mechanism is connected to the receiver.
Next comes the firing mechanism of the rifle which is housed at the bottom of the receiver .The firing mechanism consist of trigger group which has hammer,trigger spring,trigger,disconnector,disconnector spring.full automatic sear,full automatic sear spring and selector lever.
Among other major component that are housed inside the receiver are the trunnion.There is a front trunnion and a rear trunnion.The front trunnion as the name suggest sits at the front end of the receiver ,its main purpose is to attach the barrel to the receiver .The barrel is pressed and pinned into the front trunion.The rear of the barrel is pressed into trunnion,the chamber of the barrel sits inside the trunnion.The trunnion have bolt locking and carrier stop surface.When the bolt carrier travel forward the front of the bolt is locked at the mouth of the chamber present in the trunnion.The front trunnion is riveted to the front of the receiver.The three rivets at the front end ,on both side of the receiver are the same rivets which are holding the trunnion to the receiver.
The rear trunion is riveted into the back of the receiver and forms the buttstock socket, stock tang, and the carrier return spring mounting slot.You can clearly see the two rivet heads holding in the rear trunion at the rear end of the receiver from outside.
-Now we come to the buttstock of the rifle.First we are talking about the fixed wooden stock.The buttstock is made up of laminated wood.The buttstock used in the AKM is further hollowed in order to reduce weight and is longer and straighter than that of the AK-47, which assists accuracy for subsequent shots during rapid and automatic fire. The wooden stock also houses the issued cleaning kit, which is a small diameter metal tube with a twist lock cap. The kit normally contains the cleaning jag to which a piece of cloth material is wrapped around and dipped into cleaning solution. It also contains a pin punch, an assembly pin to hold the trigger, disconnector and rate reducer together while putting these back into the receiver after cleaning the weapon, and a barrel brush. The kit is secured inside the butt stock via a spring-loaded trap door in the stock's pressed sheet metal butt cap.
There was also a folding stock version for the airborne troops and armored infantry to use in combat vehicles such as the BMP,it has an under folding steel stock.Such AKM with under folding stock is called AKMS.The folding metal stock consist of two bars and a shoulder rest.On the forward ends of the bars there are lugs for stock pins and on the rear end there are lugs for the pins of the shoulder rest.In the rear end of the bars there are locks with springs which retain the shoulder rest in the service position.The stock catch holds the stock in the service and folded positions.The stock pin holds the stock to the receiver.The stamped folding stock is reinforced with impressed ridges and steel strips riveted on the internal face.
Next is pistol grip.Early pistol grip were made up of wood,then later it was replaced with Bakelite(plastic)pistol grip.The grip screw nut is a separate piece that fits down from inside the receiver through a square hole behind the trigger guard.
Then comes the trigger guard of the rifle.A trigger guard as the name suggest is a loop surrounding the trigger of a firearm and protecting it from accidental firing.The Trigger guard is stamped, and is riveted onto the bottom of the receiver.
Just in front of the front edge of the trigger guard is the magazine release lever .It is made up of a vertical metal lever called mag catch,it is a spring loaded lever .When you insert the magazine in the slot present at the bottom of the receiver and pull it backwards ,the magazine catch lock the notch present at the rear top edge of the magazine thus locking the magazine to the receiver,when this happen there is a click sound indicating that the magazine has been locked .By pushing this mag catch forward you can release the magazine from the lock and take it out form the rifle receiver.
Ahead of the mag catch is the Magazine .The older magazine were made up of sheet metal with ribbed pattern to increase body strength but were replaced with orange-red plastic magazine later.The magazine is inserted into the magazine slot opening in the bottom of the receiver and secured along the longitudinal axis with a notch in the magazine itself and a spring loaded magazine catch in front of the trigger guard.The magazine contains and feed the round ,an AKM traditional magazine has a 30 rounds capacity ,however you should load only 29 rounds and then transfer one round in the chamber with only 28 rounds in the magazine ,so as to avoid malfunctioning of the magazine spring .The magazine is curved which is famously called the "banana shape" ,this curve is because the 7.62x39 round tapers from the base to the shoulder as a result of which ,when they are stacked one over the other the rounds naturally form an angle after some rounds,because of the taper in their shape,because of this the 7.62x39 mm magazine is curved at an angle in order to accommodate the 7.62x39mm rounds in it,the curve in the magazine allow smooth movement of round along the angle.Another reason for curved AK mags is because the magazine is seated and locked in the receiver at an angle ,the curve provide that angle which enable easy seating of the magazine inside the receiver.
The steel magazine consist of a body,follower,follower spring base plate and base plate retainer.The body serves to connect all parts of the magazine and for holding 30 rounds.The upper portion of the body acts as a feeding mechanism and has flanges(a projecting flat collar also known as feed lips )for retaining each round before it is fed into the chamber.Between the flanges there is a hole for passing the feeder arm,which pushed out each round from feed mechanism as the bolt moves forward and sends the round into chamber.To the top of the magazine body are two side plates welded into it.The one at the top front which is known as catch, hold the forward portion of the magazine to the receiver,when the catch enters the notch of the receiver the lugs of the receiver limit the upward movement of the magazine.Whereas when the rear portion of the magazine is inserted into the receiver it is engaged by the magazine catch and locked into the receiver.
In the lower portion of the magazine body there are flanges for attaching the cover plate.On the rear wall there is a hole through which the last round of a fully loaded magazine can be seen.The follower transmits the force of the spring to the round and together with the feed mechanism of the magazine locate each round properly before it is fed into the chamber.It has side plates for guiding the follower feed surface.The follower spring serves to feed the round into the feed mechanism by mean of acting on the follower.
Now coming to the bayonet, a special AKM wire cutter bayonet could be attached beneath the muzzle through the bayonet lug under the gas block. .Some AKM have the single shot GP-25 grenade launcher under the fore end(lower handguard) and an additional grenade launching sight fitted above the gas tube .A special resilient butt pad was issued to minimize the effects of the recoil on the shooter shoulder.
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The original content of this article belongs to TEAM SHATRUJEET's FB page and I've been permitted to use it here for our audience.
@Bornubus
PART 1
Know all about your AK!!!
With millions of AK rifles and its variants in use all around the world ,it would not be wrong to say that AK has been able to make its own distinct mark in the world of weapons .It has been transformed into an iconic and a cult figure.
If there are many who devout AK then there are also fair share of people who detest it.Yes,there are rifle which are far more accurate ,have better ergonomics ,are lighter and have much less recoil than an AK.Still no one can deny that the AK is the most successful assault rifle in human history. In terms of the number of guns produced, duration of service, and worldwide deployment, it has no equal.
The success of the AK can be mainly attributed to its reliability ,low cost of production ,ease of mass production ,simplicity to operate with minimal working parts.
The name AK-47 is derived from the Russian words “Avtomat Kalashnikova”,here avtomat stands for automatic in russian and Kalashnikova is used in honour of its its principal designer, Mikhail Kalashnikov.The 47 represent the year 1947 ,when this rifle was first tested by the Russian Army.It is a popular theory that AK is the direct copy of german STG-44 rifle (Sturmgewehr 44/storm rifle),we are not going to dwell over it today ,as the crux of this post is to discuss the practical use of this rifle .We will make a post some other day on the history ,controversies ,development and various other variants of this rifle.
Before we start, we would like to request you to refer to the photo we have posted below to make yourself familiar to the various parts of this rifle,this will help you to understand the post ,in a much better way.We would also like to point out that the designation AK-47 is often used, generically,to refer to all Kalashnikov-pattern assault rifles.However, the AK-47 is a specific model of Kalashnikov. There have been many variants of this rifles and there have been many other rifles that have been produced based on it,however today we are going to discuss it in context of AKM specifically,as it is the most widely used variant in our country.AKM is a redesigned and improved version of the AK-47,here M stands for modernized or upgraded AK .It was introduced in 1959.The improvement on AKM over original AK 47 were that it was made with stamped sheet metal receiver, instead of the receiver of the AK-47 that was machined from a solid steel billet ,thus bringing down the cost of production as well as a reduction in the weight of the rifle.It also featured a slanted compensator at the muzzle end of the barrel to reduce muzzle rise under recoil.
Today,we will not only learn about the basic structure ,parts of an AKM but we will also learn how to live with an AK.Before we proceed any further make yourself familiar with the various parts in an AKM.
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General overview of AKM parts-
In the front end of the rifle ,at the mouth of the barrel there is a slant muzzle compensator(half cut from top at the front of the barrel of the rifle )(a compensator is a device that prevent the rifle from jumping up during firing),as you can see in the design the compensator is cut from top portion,it is to direct all the expanding hot gases towards upward direction of the muzzle of the barrel.The upward escaping gas push the muzzle downward(every action has an equal and opposite reaction) this downward force counter the jump of the rifle due to recoil and keep the rifle stable for quick follow up shots.This slanted compensator is generally screwed into the thread present in front end of the barrel,where you can mount a muzzle device of your choice,but sometimes this compensator could also be welded to barrel,in such case it can't be removed from the barrel.Beside compensator there are two other type of major muzzle device which can be used in an ak. First is muzzle brake ( a muzzle brake is a device that redirects all the escaping gases from a the muzzle towards rear of the rifle,thus pushing the rifle towards front ,this force toward the front counter the recoil force toward the rear of the rifle and thus counterbalance it .So basically muzzle brake are used to reduce the recoil of a rifle) .Second type of muzzle device is a Flash hider (as the name suggest it used in rifle to reduce the flash at the muzzle end of the rifle.When a bullet exist from the muzzle of the rifle,the gases generated by it have many particles that burn and produce bright flash,the flash hider disperse these gases in such a way that those particles are dispersed all over thus reducing the flash that is created by the burning of those particles.This diminishes distracting, blinding light experienced by the shooter in darker surroundings due to the flash of the rifle.).In the original AKM you will see the slant muzzle compensator which direct some of the gases coming out of the muzzle upwards and right,as a result it significantly reduces muzzle climb and rightward muzzle drift during very rapid fire but in later model and custom AKM you can see various design of muzzle brake and flash hider mounted on them,as per the user choice.
Just behind the muzzle device is the barrel of the rifle(basically a metal tube through which the bullet is fired).This barrel is 436mm in length(the length is upto the muzzle).It is a rifled barrel with four right-hand grooves (A rifled barrel is the one in which spiral grooves are cut inside a gun barrel, that give the bullet a spinning motion,which makes it stable during flight),those barrel which does not have any rifling or spiral grooves are called smooth bore barrel.The twist rate of the barrel is 1 in 9.45 ( twist rate refers to the rate of spin of the bullet in the rifle barrel before it comes out of it, twist rate is represented in inches per turn.For eg with twist rate of 1:9.45 the bullet will spin one revolution in 9.45inches inside the barrel,twist rate is determined by the number of spiral grooves cut inside the barrel which spin the bullet as it travel out.It’s important that your barrel has an adequate twist rate to stabilize the bullet,the ideal twist rate depend on the size of the bullet and the barrel,AKM has adequate twist rate for a 7.62x39mm bullet.)
At the rear end of this barrel ,located inside the rifle is chamber,a chamber is the portion of the barrel that holds the round, ready for firing.The chamber is especially designed and reinforced to withstand the pressure and blast from explosion of the bullet primer that propel the bullet forward,it is because of the chamber that your rifle does not explode ,despite of the mini explosion inside it,every time your fire a bullet.
-Next just behind the muzzle of the barrel there is a fixed iron sight,which is of post type,this post resemble a vertical straight line in shape .The front sight consist of a base which is held tightly to the barrel by means of pins.The front sight post is screwed at the top centre of this base,the sight post is threaded and screws into a floating cylinder that is used for windage adjustments during sighting.The front sight base also has two protecting ears(two semi circles ) on top of it covering the front sight post form both sides,these ears protect the front sight post from any disturbance from outside factors,they are integrated part of the sight block.The front sight post is covered from both the sides by these ears and at rear from the sight base to protect it,however it is left exposed from top to allow the sight adjustment tool to reach it(basically to rotate the post to adjust for elevation).The round section at the upper section of the front sight block(above the cut out area) is the foresight stud/windage drum,this can be moved left or right to adjust windage for zero.You should always remember that you can adjust your bullet impact by moving the front sight post in the opposite direction you want your bullet impact to move.For example if you want your bullet impact to go up you will have to screw in /down the front sight post ,if you want the bullet impact to go down you will have to screw out/up the front sight post.Similarly when you want the bullet impact to go towards left you will have to push the front sight post towards right,whereas when you want the bullet impact to go towards right you will have to push your front sight post towards left.You can adjust the front sight post towards left or right through the windage drum present just below the ears of the front sight post(round shape beneath the ears)It can be done using an empty cartridge and a hammer.When you are zeroing your rifle (that is your point of aim should be equal to the point of impact of the bullet at the given distance )you can adjust your front sight post for it,by moving it in the opposite direction.Basically if you want to shift the point of impact(POI) of the bullet to right,you shift the front sight post to left,if you want (POI) to move to right ,you move the front sight post to right.Similarly if you want (POI) to move down,you screw the front sight post up,if you want (POI) to go up ,you screw the front sight post down.Please note that front sight post is attached to the base of front sight by screwing it in the threaded portion in the centre meant for it.There are two circular drum on both outer side of the front sight block called windage drum,it is through them that we push the front sight post left or right.You can use an empty cartridge and a hammer to move the front sight post left or right by keeping one end of the cartridge on the windage drum and hitting it with the hammer toward the opposite direction you want your bullet impact to move.The front sight block also has a recess at its bottom ,which holds the cleaning rod head.
- Just below the barrel is a cleaning rod ,a thin metal rod used for cleaning the barrel and for checking and clearing any obstruction in the barrel.The cleaning rod head is held by a recces/a hollow space at the base of front sight block,then it goes through a hole at the base of the gas block(again situated on the barrel) and goes into a hole in the handguard retainer.The cleaning rod is held in its place by the tension between the gas block and the front sight block.
- Just after the front sight block there is a hollow metal tube going up at an 45 degree angle from the rifle barrel and then connecting the barrel with a cylindrical tube present at the the top of the barrel .This metal block connecting the rifle barrel to the cylinder is called a gas block.The basic purpose of this gas block is to divert the gases from the barrel to the cylinder above,these gases are the driving force behind the AKM operating cycle.There is a small hole drilled at the top of the barrel,this hole is drilled at 45 degree angle(now many AK have this hole drilled at 90 degree angle) ,this hole is called gas port.The purpose of the gas port is to direct the escaping gases towards the rifle gas tube ;to help in cycling the bolt carrier.Gas block is a hollow metal tube which connect this gas port with the gas tube situated above the barrel.It will be slanted at 45 degree angle to offer the escaping gas a path of least resistance as they travel from a 45 degree gas port on the barrel through the gas block towards the rear of the rifle.The gas block fits on the barrel very tightly and is locked by two pins.At the base of the gas block below the barrel is a notch/hole ,through which the cleaning rod passes.At the top the gas block has circular edge through which it is connected to the gas tube.The gas block also has few small semi circular vent holes in the side edge of its top circular end which connects to the gas tube/gas cylinder.The purpose of these holes is to vent out all the excess and foul gases and carbon out ,as once the gas has pushed the gas piston in it's rearward movement,the gas has no more job. The holes vent our the gas after the piston starts moving.(Piston head is seated in the upper circular portion of the gas block,piston head is pushed back by the pressure of the gas which travel upwards from the barrel through the gas block ,and once it meets a resistance in form of piston head,it applies it force on it thus pushing it backward,as the piston move backward it exposes the holes present in the edges of the gas block , providing a escape route to the gases.As,Once the gas piston exits the gas block the pressure is no longer needed, enough momentum has been imparted to the carrier that it continues rearward on it's own. At this point the gas exits the holes to keep the hot gases from following the tube and releasing them into the receiver.)
- Attached to the upper circular end of the gas block,just behind it is the gas tube.The gas tube is a hollow metal tube ,cylindrical in shape .Front end of the gas tube is attached to the rear end of the gas block by just inserting the some part of the front end of gas tube into the rear circular end of the gas block.Whereas at the rear end of the gas tube there is an indent which is seated inside the space in the rear sight block ,where the gas tube is locked by turning the gas tube retaining lever down at an 45 degree angle.This lever is at the right hand side of the rear sight block .The gas tube itself just acts as a guide for the gas piston,which runs through inside of the gas tube .When the piston is not cycling ,it sits inside the gas tube ,with the piston head at the rear end of the gas block.The gas tube is fluted so some of the gas flows around the piston once it's out of the gas block,to reduce friction.The upper handguard of the rifle is clamped to the top of the gas tube.Only some portion of the gas tube is visible from outside ,attached to the gas block,rest of the portion is covered by the handguard,the gas tube go till the front end of the rear sight block.Two metal ring which resemble the "u" shape are fastened on the rear end and near the front end of the gas tube,these ring are fastened on the gas tube in inverted position,on top of the gas tube will come the top part of inverted "u" ,please do note reference to "u" is to just give some idea of shape.These ring are used to clamp the upper handguard to the gas tube ,these ring are known as front and rear joining collars/handguard retainers of the gas tube.
- When you are viewing the AK from outside ,after the gas tube what you will see on the rifle is handguard.Handguard as the name suggest is to protect the shooters hand from burning form heat generated in the barrel ,as well as for the convenience of gripping the rifle.The handguard are made up of laminated wood.The handguard is divided into two parts,upper and lower as the name suggest upper handguard cover the top of the rifle .It is mounted on the gas tube ,for mounting the upper handguard on the gas tube ,first Using a wrench , gently lock across the flat side portions in back of the gas tube(this is the same portion of the gas tube that seats in the rear sight block),Now with the upper handguard upside down place it at the bottom of the gas tube and push up the handguard into the gas tube,once the hand guard sits on the gas tube,rotate the handguard with gas tube held at its position through wrench.(Remember the handguard is upside down,so basically it sits inverted on the gas tube ,when you will successfully rotate the handguard ,it will return to its original position ,and will sits on the gas tube with the upside of the handguard on top,by doing this you will basically lock the handguard on the gas tube.The upper handguard has 4 recesses/cut out portion at its bottom end ,two on each side.These are there for air circulation to assist in cooling of the barrel,as the barrel tend to heat up from sustained firing of bullets from it.(these are basically cut at the bottom of the handguard which make space,opening,vent for the airflow,so as to vent out the heat of the barrel easily).There is a metal pressure clip seated inside the handguard,this help the handguard to clamp on the gas tube.As the handguard is already attached to the gas tube ,we do not need to retain the handguard on the rifle,it is retained along with the gas tube ,which is installed with its forward end in the gas block and its rear end in the notch of the rear sight base and is locked by means of a gas tube retaining lever present on the rear sight block.
-Similar to the upper handguard the lower handguard is also made up of laminated wood.The lower handguard is also known as fore-end .It is large at the rear and tapers(narrow down) at the front.It has got 4 recesses(vents cut out ),two at each side at its bottom.There is a horizontal bulge at its centre on both side,it is there to aid in gripping the rifle.There is also a thin U shaped metal clamp inside the handguard ,which protects the handguard from wrapping or sticking to the barrel.The lower handguard is installed on the barrel of the rifle ,upside down.For installing lower handguard there is a handguard retainer ring,which is a metal ring ,that is mounted on the barrel of the rifle,this handguard retainer ring has a small hole at its bottom,through which the cleaning rod passes.It also has a side ring which is used to mount the sling of the rifle.This retainer ring can be slided forward and back on the barrel.When you have to install the lower handguard just slide this retainer ring to the front of the barrel ,near the gas block.Now push up the lower handguard upside down ,on the barrel.At the back of the wooden handguard there will be a wooden tab protruding out,slide this wooden tab in the opening at the front of the receiver ,below the barrel.Through this you will be attaching the rear of the handguard to the front of the rifle receiver .Now slide back the handguard retainer ring present on the barrel (which you have slided forward a while ago)When the retainer ring reaches the front end of the handguard .Now there will be a small lever ,which will be facing towards the muzzle of the rifle,push this lever at 180 degree angle ,inside the lower handguard pointing towards the rear of the rifle and in line with the barrel of the rifle.Once this lever is pushed towards the handguard side,the retainer ring will lock the handguard in its place.
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-Please do note that later on the russian themselves ,as well as the others in the world moved away from the wooden handguard ,to polymer handguards for the AKM.
-Right after the front handguard , the rear sight block of the AKM is located at the top of the rifle.It is a rear "U" notched type open iron sight ,with elevation for different ranges.The rear sight block consist of a base and a sight leaf at the top of the base.The sight leaf is mounted on a ramp ,which is part of the base.The sight base has a lug/hole,by means of which the sight is mounted on the barrel with help of a pin,which hold the base on the barrel.A gas tube lock lever is located out,on the right hand side of the base .Turning this lever to 45 degree down locks the rear of the gas tube into the base,whereas turning this lever up will release the gas tube from the base.The sectors or the ramp is integral with the top of the sight base and is used to set the desired ranges.The sight leaf have markings for shooting at different distances measured in meters.The adjustments are intended to change the ballistic trajectory so that point of aim and point of impact are the same at the respective distance selected on the sight.The sight leaf has odd numbers inscribed on the right side from 1 to 9 ,which represent the ranges of 100 to 900 meters .On the left side there are inscribed even numbers from 2 to 10,which correspond to ranges of 200 to 1000 meters.On the left side of the sight leaf is the letter "p"(Symbol could be different depending on the country of origin).It is located at the rear most position on the sight leaf below the number 1.The rear sight leaf has a sight bar with rectangular notches for the catch teeth ,longitudinal notch for the exact indexing of the inscribed number .
-The metal body right behind the lower handguard is the receiver of the AKM,before we dwell further regarding the details of the receiver on the AKM ,let's first understand the concept of receiver.A receiver is a frame or that part of rifle which house the breech block, bolt and the firing mechanism of the rifle.In AKM and most of the rifles receiver is usually single body housing all the components named above ,however in some rifle like the m16,ar 15 design the receiver is divided into 2 parts instead of one single body.The receiver in an ar 15 rifle is divided into upper and lower ,where the top part is housing the barrel and bolt while the lower part is housing the trigger group, the two parts are held together by a pin ,by disengaging the pin you can separate the two.
Now returning back to the AKM ,the receiver of the AKM is made from the stamped sheet steel, with machined steel inserts riveted into the place where required.In a stamped receiver a flat piece of thin metal sheet is stamped and bent into a box shape and riveted with a center spacer with both front and rear trunnions.The other type of receiver commonly found in rifles is machined/milled receiver ,here each receiver is machined from a block of steel into shape rather than stamping various sheet of steel into a particular shape. All the internal guide rails, magazine well and latch surfaces, bolt locking surfaces, bolt carrier stop, and the barrel and buttstock receiving sockets, were cut into the same, single piece of steel.We will talk about the differences among these two receiver some other day.
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However ,since we are talking about the stamped and machined receiver you must be wondering how you can differentiate between the two.There are two ways to visually differentiate between a machined and a stamped receiver
1 .A machined receiver has a large horizontal rectangular shaped cut-out , which is nearly 5 inches long on each side of the receiver, above the magazine slot ,at the lower edge of the receiver. It was designed to reduce the overall weight of the rifle.Just look above the portion where you have inserted the magazine of the rifle.Whereas in a stamped receiver at the same position on each side of the receiver ,instead of a rectangular cutout we have a small, shallow indentation,about 1-inch long .You can see a smaller, more rounded dimple just above where the magazine is inserted this dimple is known as "magazine guide".
Please note that the purpose of the dimple in the stamped receiver and the rectangular cut in the machined receiver is totally different .The dimple is there to act as the magazine guide,it act as the indicator of the centre point of the magazine ,when the magazine is inserted into the receiver.Whereas the rectangular slot in the machined receiver is done to reduce the weight of the receiver by slicing off some metal,also do remember that both the dimple and the rectangular slot are on both side of the receiver at corresponding positions.
2. Other method for differentiating between the two receiver is to check the rear of both the receiver by removing the rifle stock.The design of the rear side of both the receiver is different .Where is stamped you a a open rectangular opening in a machined receiver you have a narrow inverted "U" shaped opening(please refer to the photo).Due to this difference is design the stock of a stamped receiver AKM cannot be mounted on a machined receiver AKM and vice -versa.
While we are at it,let's learn the brief history of AK receiver.The soviet experimented with 4 different receivers (including the present stamped one) before they settled for the stamped receiver which you see in the AKM,which is the 4th and final receiver .The first receiver of Ak rifle was made from a sheet steel stamping fitted with a machined steel trunnion into which the breech of the barrel was fitted.But there were problem in welding the internal component to this type of receiver ,the heat generated from the welding used to cause the receiver to bent making it unsuitable.As a result of this a second method of production was used to manufacture the receiver ,that was machined receiver -the method of maching the receiver from a solid block of steel.The machined receiver ,which will be the 2nd type was heavier but stronger than the stamped receiver and had rectified the problem of bending due to heat faced in the previous (1st) receiver.However a new problem cropped up in this type of receiver .The fitting of existing stock was having difficulty in this type of receiver ,that led to redesigning of this receiver .The 3rd receiver was also a machined one but it differed from the 2nd receiver mainly in the method of fixing the stock to the receiver.Although the machined receiver were working fine ,they were complex,expensive to produce and were heavy ,which led to the designers to continue to find the solution of the problem faced in the 1st type stamped receiver.With the help of simple changes to the design and production methods and with the help of various german engineer working in Russia ,they were able to eventually overcome the problems they faced with stamped receiver.Some of the changes were less use of welding and more use of riveting and stamped parts.These improvement resulted in the type of 4 stamped receiver,and a new weapon designation -the Avtomat Kalashnikova Modernizirovanniy or AKM.The type 4 receiver first appeared during 1955,but it was not until 1959 that the design had been sufficiently developed for it to be accepted into service as the standard weapon type.
Now coming back to the stamped AKM receiver which we are discussing.The Russian AKM receiver is stamped from a flat sheet of thin metal, bent into its "U" box shape, and riveted together with a center spacer and both a front and rear trunnion(A trunnion is something which is used as a mounting and pivoting point). Instead of being pinned or threaded directly into the receiver as in a milled receiver, the barrel for a stamped AK is pinned into a barrel trunion,located at the front of the receiver. The front trunnion contains the bolt locking and carrier stop surfaces. The trunnion is then riveted into the front of the receiver. Similarly, a rear trunnion is riveted into the back of the receiver and forms the buttstock socket, stock tang, and the carrier return spring mounting slot.
On the exterior of the receiver,at left side in the front,just behind the top portion of the rear of the lower handguard, there is the serial number of the rifle ,year of manufacture and factory marking of the rifle.The three protruding rivet heads which can be seen at the front of the receiver are the rivets that are holding the front trunnion inside the receiver ,similarly two rivet head can be seen at the rear end of the receiver which are holding the rear trunnion inside the receiver.These rivets can also be seen from the right hand side of the receiver ,as these are the rivet points of the front and rear trunnion.The circular weld marks for the internal bolt guide are also clearly visible on the side of the receiver.There is also a small depression or dimple just above the magazine slot of the receiver ,this act as a magazine guide .There are two dimple at corresponding to each other on both sides of the receiver ,these dimples act as the magazine guide that keep the magazine centered in the rifle.
On the right side of the AKM receiver ,just above the pistol grip you can see the selector lever of the AKM ,this selector lever has added central reinforcing rib,the selector lever as the name suggest is used to select firing mode of the rifle.Just above the rear end of the magazine slot ,there are markings that are stamped on the receiver ,these marking indicate the firing mode for the selector lever.Always remember the topmost position is for safe,middle position of the lever is for automatic/burst and the bottom position is for single shot in AKM and please note there is no marking for safe position you must know that topmost position is for safe,rest there are marking at middle and bottom for automatic and single shot respectively.The receiver also has a selector stop to prevent the selector lever being force down too far.It is positioned above the forward edge of the trigger guard.
At the front top edge of the receiver ,there is a metal tab protruding out of the receiver ,this is called charging/cocking handle,It is permanently attached to the bolt carrier(we will talk about it after this) and reciprocates(move rearward and forward) when the rifle is fired.Just above the position where charging handle is placed when at rest, is the ejection port,it is a 45 degree angle slot which ejects out the spent casing of the bullet when the bolt carrier move rearward.When the rifle is not firing this ejection port is covered by the bolt carrier ,it is exposed only when the bolt carrier move backward ,either on its own or either by manually pushing back the bolt carrier through the charging handle that is protruding out.
On top of the receiver is the top cover also known as dust cover/receiver cover ,as the name suggest it is a cover for the receiver .The top cover is there to protect the receiver from outside elements and preventing dust from going in the receiver.The top cover is made up thinner sheet metal than the one used for the receiver,hence to strengthen the top cover a series of ribs have been stamped on the top cover(the rib pattern on the top cover can be clearly seen,these are for strengthening the top cover).This top cover has a rectangular slot at its rear ,through which the recoil spring guide lug passes and locks the top cover to the rifle.The top cover is fastened to the receiver by its forward face,which enters a semicircular groove in the base of the rear sight,and by means of the lug of the return spring guide rear end,which enters the opening in the rear wall of the receiver cover.The top cover is designed in such a way ,that when it is seated over the receiver ,it leaves a slot in the front half area between it and the receiver,this area is left to aid the rearward movement of the bolt carrier and the charging handle protruding out of it as well as for the ejection port.
Inside the receiver there is a rigid tubular cross-section support that adds structural strength to the receiver.At top end of the inside of the receiver there are two rails ,one on each side facing each other ,these are known as top rails.Just below the top rails at some gap are two guide rails ,one on each side.The purpose of these rails is to aid in sliding of the bolt carrier group .The left hand side guide rail(which is below the top rail ) has a shark fin type indent protruding out,this is known as ejector as the empty casing are pushed outside the rifle by it as they are moving backward along with the bolt carrier group.(To understand the design of the top rail and the guide rail please refer to the photo )
At the rear end of the receiver there is a slot ,through which the butstock of the rifle is attached to the rear trunnion.At the bottom of the receiver there are three slot,front one for magazine slot,middle one for trigger and the rear one for the pistol grip.
Talking about the main component which are housed inside the receiver;first and foremost we will talk about the bolt carrier group.Bolt carrier group has the operating rod ,which is the main body of the bolt carrier ,to the operating rod at the front piston rod is attached,whereas the bolt sits in a cylindrical body at the bottom of the operating rod.This is known as bolt carrier group.
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The bolt carrier group comprise of bolt carrier ,piston and bolt
Bolt carrier-
Bolt carrier has a hollow rod at the top known as the operating rod,a piston rod is attached at the front of the operating rod by means of threads and pin which is installed in a hole present in the forward end of the operating rod.
The bolt carrier has a has a cylindrical channel at its rear end in which the rear end of the bolt is installed.In the sides of the bolt carrier there are grooves which guides the operating rod in the receiver by riding on the guide rails present in the receiver.On the right side there is a lug which disconnects the automatic sear and is called the full automatic disconnector.On the left side there is a notch for passing the ejector.Bolt carrier also have a rear bevel for smooth cocking of the hammer when the operating rod is moving to the rear and a forward bevel for depressing the cocked hammer as the operating rod is moving forward.
On the right side of the bolt carrier there is a charging handle integrated to it.
In the central portion of the bolt carrier there is a cam surface on which the bolt guide lug rides.The bolt rotates due to its the movement of its guide lug on this cam surface.This cam surface act as railway track and the lug on the bolt act as the wheel of a train which are set on the tracks.As the bolt carrier move forward or rear- ward the tracks passes through the guide lug on the bolt causing the rotation of the bolt.
Bolt -
The bolt consist of a body,firing pin,spring loaded extractor and two retaining pin-one for firing pin and other for extractor.
The bolt head(front portion of the bolt) has a right and left lugs ,which locks with the receiver lugs when the bolt rotates clockwise.It has a guide lug ,which when travel through the cam track machined in the bolt carrier causes the bolt to rotate.Then the bolt head also have a forward edge ,which pushes out the top most round from the magazine and feed it into the chamber ,through a ramp.
The bolt also have extractor (a metal claw) in ihe front face of the bolt.The extractor which is spring loaded grasp the rim of the cartridge as it is pushed inside the chamber ,when a round is fired the extractor pull out the cartridge from the chamber.The extractor with spring is installed in the bolt in the bolt head by means of pin.In the bolt body there is a longitudinal groove for passing the extractor,in the rear portion the groove is made wider for passing the extractor when the bolt is rotating as the chamber is being sealed or opened.
In the center of the body there is a channel for housing the firing pin.In the forward position the channel is conical in shape,and the other end terminates in a hole for passing the tip of the firing pin.The firing pin when struck by the hammer at rear ,pierces the primer of the cartridge setting it off.
The firing pin is divided into the rear and the forward portion .The portion terminates in the tip of the firing pin1,in the rear portion there are three longitudinal grooves for decreasing the weight of the firing pin and for decreasing friction as it moves in the channel in the bolt body.The firing pin is prevented from falling out of the bol body by a retaining pin,which passes a notch in the firing pin.
Piston -
To the operating rod of the bolt carrier the piston rod is attached at the front top portion by means of threads and pin which is installed in hole in a hole present in the forward end of the operating rod.A piston in simple terms is a metal rod with a head which is attached to he operating rod and form a part of the bolt carrier.Piston head receives the pressure of the gases in the gas block and start moving rearward,the piston rod transfer this momentum to the operating rod which also start moving rearward resulting in whole bolt carrier moving back(bolt carrier group = bolt carrier+piston+bolt)
On the forward face of the piston there is a sharp rim which scrapes off carbon from the walls of the gas cylinder as the operating rod moves.
Charging handle -
The charging handle is a metal tab present at the right top hand of the bolt carrier and protruding out from the right side of the receiver.It is called charging/cocking handle because by pulling it to the rear and then releasing it ,by which it return back to the front you charge,cock the rifle that is cock the hammer and chamber a round if there is one in the magazine.This process is called charging or cocking the rifle.
When the escaping gases hit the piston head seated in the gas block,it is pushed backward ,when the piston rod travel backward,the whole bolt carrier group travel backwards in the receiver ,as the bolt carrier group travel backwards, it cocks the hammer ,when it reaches the rear of the receiver it is pushed forward by the recoil spring connected at the rear channel present in the bolt carrier group .So this is how the bolt carrier group move inside the receiver when rifle is fired.
The return mechanism inside the receiver consist of return spring,guide ,guide rod .The return spring as the name suggest is a spring which is placed horizontally at the rear of the receiver ,its head is placed inside the channel,present at the top rear edge of the bolt carrier group.It is connected to the bolt carrier group through it.The return spring return the bolt carrier to the extreme forward position after firing.The guide and the guide rod are metal rods on which the return spring ride during its movement ,these rod prevent the return spring from bending and help in keeping it straight.Guide rod is at the front of the return spring and the guide at the rear portion ,the return spring is placed over these rods.On the inside forward portion of the guide there is a shoulder which stops the guide rod ,when the return spring travel rearwards.The guide also has a lug at its rear ,through which the return mechanism is connected to the receiver.
Next comes the firing mechanism of the rifle which is housed at the bottom of the receiver .The firing mechanism consist of trigger group which has hammer,trigger spring,trigger,disconnector,disconnector spring.full automatic sear,full automatic sear spring and selector lever.
Among other major component that are housed inside the receiver are the trunnion.There is a front trunnion and a rear trunnion.The front trunnion as the name suggest sits at the front end of the receiver ,its main purpose is to attach the barrel to the receiver .The barrel is pressed and pinned into the front trunion.The rear of the barrel is pressed into trunnion,the chamber of the barrel sits inside the trunnion.The trunnion have bolt locking and carrier stop surface.When the bolt carrier travel forward the front of the bolt is locked at the mouth of the chamber present in the trunnion.The front trunnion is riveted to the front of the receiver.The three rivets at the front end ,on both side of the receiver are the same rivets which are holding the trunnion to the receiver.
The rear trunion is riveted into the back of the receiver and forms the buttstock socket, stock tang, and the carrier return spring mounting slot.You can clearly see the two rivet heads holding in the rear trunion at the rear end of the receiver from outside.
-Now we come to the buttstock of the rifle.First we are talking about the fixed wooden stock.The buttstock is made up of laminated wood.The buttstock used in the AKM is further hollowed in order to reduce weight and is longer and straighter than that of the AK-47, which assists accuracy for subsequent shots during rapid and automatic fire. The wooden stock also houses the issued cleaning kit, which is a small diameter metal tube with a twist lock cap. The kit normally contains the cleaning jag to which a piece of cloth material is wrapped around and dipped into cleaning solution. It also contains a pin punch, an assembly pin to hold the trigger, disconnector and rate reducer together while putting these back into the receiver after cleaning the weapon, and a barrel brush. The kit is secured inside the butt stock via a spring-loaded trap door in the stock's pressed sheet metal butt cap.
There was also a folding stock version for the airborne troops and armored infantry to use in combat vehicles such as the BMP,it has an under folding steel stock.Such AKM with under folding stock is called AKMS.The folding metal stock consist of two bars and a shoulder rest.On the forward ends of the bars there are lugs for stock pins and on the rear end there are lugs for the pins of the shoulder rest.In the rear end of the bars there are locks with springs which retain the shoulder rest in the service position.The stock catch holds the stock in the service and folded positions.The stock pin holds the stock to the receiver.The stamped folding stock is reinforced with impressed ridges and steel strips riveted on the internal face.
Next is pistol grip.Early pistol grip were made up of wood,then later it was replaced with Bakelite(plastic)pistol grip.The grip screw nut is a separate piece that fits down from inside the receiver through a square hole behind the trigger guard.
Then comes the trigger guard of the rifle.A trigger guard as the name suggest is a loop surrounding the trigger of a firearm and protecting it from accidental firing.The Trigger guard is stamped, and is riveted onto the bottom of the receiver.
Just in front of the front edge of the trigger guard is the magazine release lever .It is made up of a vertical metal lever called mag catch,it is a spring loaded lever .When you insert the magazine in the slot present at the bottom of the receiver and pull it backwards ,the magazine catch lock the notch present at the rear top edge of the magazine thus locking the magazine to the receiver,when this happen there is a click sound indicating that the magazine has been locked .By pushing this mag catch forward you can release the magazine from the lock and take it out form the rifle receiver.
Ahead of the mag catch is the Magazine .The older magazine were made up of sheet metal with ribbed pattern to increase body strength but were replaced with orange-red plastic magazine later.The magazine is inserted into the magazine slot opening in the bottom of the receiver and secured along the longitudinal axis with a notch in the magazine itself and a spring loaded magazine catch in front of the trigger guard.The magazine contains and feed the round ,an AKM traditional magazine has a 30 rounds capacity ,however you should load only 29 rounds and then transfer one round in the chamber with only 28 rounds in the magazine ,so as to avoid malfunctioning of the magazine spring .The magazine is curved which is famously called the "banana shape" ,this curve is because the 7.62x39 round tapers from the base to the shoulder as a result of which ,when they are stacked one over the other the rounds naturally form an angle after some rounds,because of the taper in their shape,because of this the 7.62x39 mm magazine is curved at an angle in order to accommodate the 7.62x39mm rounds in it,the curve in the magazine allow smooth movement of round along the angle.Another reason for curved AK mags is because the magazine is seated and locked in the receiver at an angle ,the curve provide that angle which enable easy seating of the magazine inside the receiver.
The steel magazine consist of a body,follower,follower spring base plate and base plate retainer.The body serves to connect all parts of the magazine and for holding 30 rounds.The upper portion of the body acts as a feeding mechanism and has flanges(a projecting flat collar also known as feed lips )for retaining each round before it is fed into the chamber.Between the flanges there is a hole for passing the feeder arm,which pushed out each round from feed mechanism as the bolt moves forward and sends the round into chamber.To the top of the magazine body are two side plates welded into it.The one at the top front which is known as catch, hold the forward portion of the magazine to the receiver,when the catch enters the notch of the receiver the lugs of the receiver limit the upward movement of the magazine.Whereas when the rear portion of the magazine is inserted into the receiver it is engaged by the magazine catch and locked into the receiver.
In the lower portion of the magazine body there are flanges for attaching the cover plate.On the rear wall there is a hole through which the last round of a fully loaded magazine can be seen.The follower transmits the force of the spring to the round and together with the feed mechanism of the magazine locate each round properly before it is fed into the chamber.It has side plates for guiding the follower feed surface.The follower spring serves to feed the round into the feed mechanism by mean of acting on the follower.
Now coming to the bayonet, a special AKM wire cutter bayonet could be attached beneath the muzzle through the bayonet lug under the gas block. .Some AKM have the single shot GP-25 grenade launcher under the fore end(lower handguard) and an additional grenade launching sight fitted above the gas tube .A special resilient butt pad was issued to minimize the effects of the recoil on the shooter shoulder.
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