The Kalashnikov series of rifles, more commonly known as AKs, are gas-operated assault rifles designed by former Soviet Army Lieutenant General Mikhail Kalashnikov, and is produced primarily in former Soviet bloc countries, as well as some Middle Eastern and South Asian countries. It currently serves as the service rifle in several of the aforementioned nations (as well as most African nations), and comes in several different calibers and makes, each with distinctive features.
History
AK (always incorrectly called AK-47) stands for Автомат Калашникова образца 1947 года (Avtomat Kalashnikova, obraztsa 1947 goda), which translates to "Kalashnikov's automatic weapon", model of the year 1947.
The AK never had a production designation by the name "AK-47", and has been produced by the Izhevsk Mechanical plant under the "Avtomat Kalashnikova AK" designation. Still, the "AK-47" designation stuck to the AK, likely because most Russian weapons have a design date in their names.
History Of AK-47
Sergeant Mikhail Kalashnikov, being in the hospital after being wounded, began to develop various small arms during World War II. In 1944 he was assigned to the Izhevsk Machinebuilding Plant (IZHMASH), where he developed a semi-automatic, gas-operated carbine. Starting with this design, based on (and outwardly resembling) the German Sturmgewehr 44 (StG 44 or MP44/MP43), he developed an assault rifle that he submitted for official Soviet Army trials in 1946.
During 1946 and early 1947, he redesigned his initial rifle and submitted it to the second trials, held in 1947. The new prototype was deemed superior to the other competitors and was consequently adopted in 1949 as the "7,62mm Avtomat Kalashnikova, obraztsa 1947 goda" (7.62mm Kalashnikov automatic rifle, model of 1947). After extensive field trials it was slightly modified in 1951, but retained the same name. Along with the basic version, a folding stock version had been developed for paratroopers and vehicle crews and was named the AKS.
By 1959, the AK was modified again, this time more extensively, and was consequently adopted (after trials) as the AKM (Avtomat Kalashnikova Modernizirovannyj - Kalashnikov Automatic rifle, Modified). The key changes were the introduction of the stamped receiver instead of the milled one, and improved trigger/hammer unit that introduced a hammer release delay device (often incorrectly referred to as a rate reducer). Other changes were effected, to include a slightly raised buttstock, the pistol grip, and the addition of the removable muzzle flip compensator. This spoon-like compensator is screwed onto the muzzle and uses the muzzle blast to reduce muzzle climb during bursts of automatic fire.
Design details
AKs are long-stroke gas piston operated rifles. Most AKs are select-fire rifles; some have been converted to only fire semi-automatically. In all cases, the selector doubles as a dust cover; when the rifle is on SAFE, the selector covers the ejection port.
Receivers
Early AKs have milled steel receivers. These are identified by two milled out sections, right above the magazine well, one on each side of the receiver. These are known as AK receivers, and were rather expensive to produce.
Most modern AKs use stamped sheet metal receivers. The metal is 1mm thick. These receivers, with a couple of exceptions (Romanian WASR-10 rifles, Saiga rifles), have two dimples, one on each side of the receiver, that serve as magazine guides. These receivers can also be identified by the rivets that hold the front trunnion in the receiver. These receivers are found on AKM rifles, AK-74 rifles, and all rifles of the AK-10X lineage.
Some AKs (Yugoslavian rifles, some Chinese rifles, and all RPKs) have reinforced stamped sheet metal receivers; the metal is 1.6mm thick, instead of 1mm. These can be identified by the rivet that holds the front trunnion in the receiver; it is oversized and reinforced. These tend to be very durable and stable receivers.
Operating system
The piston rod (op rod, actuator rod) is permanently attached to the bolt carrier. The bolt carrier rides on the two rails machined in the receiver with significant clearances between the moving and stationary parts.
The bolt has two lugs that lock into the barrel extension, sealing the chamber when it goes into battery. Upon unlocking, it makes a primary extraction movement on the spent case. This, along with the significant taper of the 7.62x39mm and 5.45x39mm casing, results in very positive and reliable extraction, even with a dirty chamber and dirty or corroded cases. The rotation of the bolt is ensured by the curved cam track, machined in the bolt carrier, and by the appropriate stud on the bolt itself. The action spring and spring guide are located behind the gas piston and are partially hidden in its hollow rear part when the bolt is in battery. The base of the action spring assembly also serves as a receiver cover lock; the serrated end holds the cover down. The charging handle is permanently attached to the bolt carrier (in fact, it forms a single machined steel unit with the carrier), and does reciprocate when the weapon is fired.
Gas block and barrel assembly
The gas block is located on the barrel, and the gas port on modern AKs is drilled at 90 degrees; this was changed from the original 45 degrees due to 5.45mm bullets shearing in the barrel. Generally speaking, there are two thread pitches for the muzzle. AKs and AKMs use a 14/1mm left hand thread, and the barrel itself is threaded. AK-74s use a front sight assembly that slips over the barrel itself, and is threaded. Russian, Bulgarian, and East German AK-74s use a 24mm right-hand thread, while Romanians use a 22mm right-hand thread.
Most AKs, with a couple of exceptions (Yugoslavian rifles and their clones do not have chrome-lined bores), have cold hammer forged barrels with chrome-lined bores to resist corrosion.
Sights
The Kalashnikov rifles feature rear sights adjustable for range (100 to 800 meters on an AK, 100 to 1000 on everything else), and a front sight, adjustable for elevation and windage. The rear sight is adjusted by pressing in on the slide catch and moving the slide bar along the leaf until the front edge of the bar is aligned with the line below the number that corresponds with the range in meters.
The front sight post is adjusted for elevation by screwing it in and out of the front sight base; a wrench is used to do this. Windage is adjusted by using a tool to move the front sight post mount from side to side. A 1mm adjustment of the front sight changes the point of impact by 26 cm at 100 meters on a 7.62 Soviet AK.[1]
Manual of arms
AKs are short, compact, gas-operated, select-fire weapons. They feed from 30-round box magazines, which have a significant curve if the AK in question is of the 7.62 Soviet variety; 5.45 Russian and 5.56 NATO magazines are straighter, with the 5.45 having a slightly more significant curve due to the taper of its casing.
The magazine is inserted via a "rocking" motion, positioned so that the lug on the front of the magazine engages with its recess in the magazine well, into the magazine well. It should be pulled to the rear until it snaps into place.
In order to operate the charging handle, the selector must be off safe. The charging handle is pulled all the way to the rear and then released to chamber a round. As the bolt carrier goes forward, the lug on the bottom of the bolt will strip a round out of the magazine and feed it into the chamber.
When a round is fired, the gas produced by the propellant in the cartridge goes into the gas tube and impinges upon the operating rod, which then unlocks the bolt and cycles the bolt carrier rearward, which causes it to cock the hammer as it travels. The bolt carrier then strips another round from the magazine and chambers it as it travels forward, and locks the bolt, sealing the round in the chamber.
When the last round is fired, there is no bolt catch mechanism to catch the bolt carrier group and prevent it from closing on an empty chamber. Thus, when the shooter reloads, he will need to rack the charging handle to chamber the next round. If the shooter experiences a malfunction, in most cases racking the charging handle (or reloading, if the magazine is bad OR empty), will solve the problem.
Variants
There are several variants of the Kalashnikov rifle, in different calibers and of differing configurations. This section will not list the varying models by country, unless they do not fit under any other variant listed here.
7.62 Soviet rifles
AK
This AK is chambered for 7.62x39mm. It has a milled receiver, a 45 degree gas block, and no muzzle device; the muzzle threads are protected by a muzzle nut. This rifle features wooden furniture, and does not have a hammer release delay device. It features a 16 inch barrel.
This is the model often incorrectly labeled as AK-47; there is no number denoting the year of manufacture.
AKS
Same as the AK, but with a wire underfolder stock.
AKM
The most produced version, this AK is chambered for 7.62x39mm ammunition. It has a stamped sheet metal receiver which is 1mm thick. It has two dimples, one on each side of the receiver, above the magazine well, that serve as magazine guides. Romanian WASR-10 rifles do not have these indentations (though they are correctly referred to as AKMs when converted to take standard double-stack magazines). Some variants, such as the Yugoslavian Zastava M70, utilize a thicker RPK receiver, rather than the normal 1mm receiver.
AKMs have a 45 degree (slanted) gas block, and the barrel is no longer threaded to the receiver; it is embedded using a 20-ton press and secured with a pin. The barrel assembly has horizontal guide slots to help align and keep the handguards in place. The "spoon" muzzle device is in place to combat the weapon's tendency to climb up and left on full auto. The barrel length for this weapon is 16 inches.
The AKM has a modified trigger assembly, equipped with a hammer-release delaying device (installed on the same axis pin together with the trigger and semi-automatic sear). This device also prevents the weapon from firing out of battery.
The AKM's bolt carrier group is slightly lighter than the AK's bolt carrier group; despite this, the two are completely interchangeable in an AKM rifle.
The wooden stock used in the AKM is further hollowed in order to reduce weight and is different in shape to a small degree.
The AKM uses a modified return spring mechanism, which replaces the single recoil spring guide rod with a dual “U”-shaped wire guide.
The rear sight is adjustable for ranges from 100 to 1000 meters, as opposed to the AK's 100 to 800 meters.
AKMS
Same as the AKM, only with a wire underfolder stock.
AK-103
This rifle is the 7.62 Soviet variant of the full-size (non-carbine) AK-10X lineup. Unlike the earlier 7.62 AKs, this one has a 90 degree gas block, as well as the other AK-10X upgrades. The AK-103 features an AK-74-style muzzle brake and has a barrel length of 16 inches. This rifle is in service with selected units in the Russian military.
RPK
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The RPK is the light machine gun variant of the Kalashnikov rifle. It comes with a 24-inch heavy barrel and its receiver is stamped sheet metal that is 1.6mm thick, and has an oversized and reinforced rivet holding the front trunnion. These can take either standard 30- or 40-round magazines (the 40-round magazines were standard issue for an RPK gunner, along with one 75-round drum), or 75-round drums. This variant comes in 7.62 Soviet. Production for this weapon began in 1961, and ended in 1978.
Unlike most other weapons in its class, the RPK fires from a closed bolt.
7.62 Soviet carbines
Draco
The Draco Carbine is a short Romanian 7.62 Soviet carbine variant of the AKM rifle. It features a very short barrel and a wire sidefolder stock. Draco carbines exported to the U.S. have the stock removed and are sold as pistols.
AK-104
This is the shortened, carbine version of the AK-103. It is chambered for 7.62 Soviet, and features a 12 inch barrel and the same muzzle device as the AKS-74U, designed to help the weapon cycle.
5.45x39mm rifles
AK-74
This AK is chambered for 5.45x39mm ammunition, and features all the upgrades that were made to the AKM. Early AK-74 rifles featured a 45 degree gas block; these were changed to 90 degrees when bullet shear became an issue for the 5.45mm rounds. This rifle features a front sight assembly that slips over the barrel, and is threaded for muzzle attachments. It has a muzzle brake installed, and features a 16-inch barrel.
As with the WASR-10, the WASR-2 (a Romanian AK-74) does not have the dimples in the receiver over the magazine well.
AKS-74
Same as the AK-74, only with a side-folder wire stock.
AK-74M
The AK-74M is functionally the same rifle as the AK-74; however, the wooden furniture has been upgraded to polymer and the barrel is now cold hammer forged, making it more durable, AK-74M has received a stock, folding to the left. The flash suppressor has been changed too; the new one has open cameras for being able to be cleaned without detaching. The AK-74M also received a side rail, universal for all Russian day/night optics. The rifle is lighter and stronger than its wooden-furniture counterparts. It is the current service rifle of the Russian military.
RPK-74
This is the light machine gun variant of the Kalashnikov rifle, but with the AK-74 upgrades. It is chambered in 5.45x39mm and can take standard AK-74 magazines, 45-round magazines, 60-round magazines, and 100-round drums. Its receiver is stamped sheet metal, 1.6mm thick, and it has a 24-inch heavy barrel. The magazine well and rear trunnion are also reinforced, making for a very strong, very durable receiver.
RPK-74M
This is the light machine gun variant of the Kalashnikov rifle, with the AK-74M upgrades, though it is functionally the same as the RPK-74. It is chambered in 5.45x39mm and can take standard AK-74 magazines, 45-round magazines, 60-round magazines, and 100-round drums. The 45-round magazines for this weapon are polymer, like the magazines for the AK-74M. The receiver is stamped sheet metal, 1.6mm thick, and the RPK-74M sports a 24-inch heavy barrel.
RPKS-74
The RPKS-74 is a light machine gun designed and manufactured in Romania. It is an RPK clone with a folding wire stock and a four-position fire selector with burst fire compatibility, an unusual aspect for a Kalashnikov variant. Some RPKS-74s were made with scope rails fitted and Bakelite handguards. The RPKS-74 was produced in the early 90s.
5.45x39mm carbines
AKS-74U
Carbine version of the AK-74. It features a triangular folding stock and a 8.3-inch barrel with a 1:6.3 twist to better stabilize the 5.45mm projectile from the short barrel.
A new gas block was installed at the muzzle with a new conical flash hider combined with a cylindrical muzzle booster, which features an internal expansion chamber that increases the weapon's reliability by ensuring that the weapon cycles completely upon firing. The booster enhances the recoil impulse by supplying the gas system with residual gases from the barrel. The chrome-lined muzzle booster also burns any remaining propellant, thus reducing the gun's flash signature. The muzzle device locks into the gas block with a spring-loaded detent and features two notches cut into the flash hider cone, used for disassembly using the supplied cleaning rod. The forward sling loop was relocated to the left side of the carbine and the front sight was integrated into the gas block.
The AKS-74U also has a different sighting system, with a U-shaped flip sight instead of the standard sliding notch rear sight. This sight has two settings: "P" (calibrated for firing at 350 m) and "4–5" (used for firing at distances between 400–500 m). The rear sight is housed in a semi-shrouded protective enclosure that is riveted to the receiver's top cover. This top cover is integral with the gas tube cover and hinged from the barrel trunnion, pivoting forward when opened. Both the gas tube and handguard are also of a new type and are shorter than the analogous parts in the AKS-74.
AK-105
This is the shortened, carbine version of the AK-74M. It is chambered for 5.45 Russian ammunition, and features a 12 inch barrel and the same muzzle device as the AKS-74U, designed to help the weapon cycle.
5.56 NATO rifles/carbines
AK-101
This rifle is chambered in 5.56 NATO. It features most of the upgrades available on the AK-74 and AK-74M. The rear and front trunnions have been redesigned, the handguards now have a heat shield inside, and the AK-101 has an optical plate on the side for installation of Russian and European AK optics. This rifle is the export version of the AK-74M, and production of this rifle started in 1990.
AK-102
This rifle is a 5.56 NATO version of the AK-105, and a compact, carbine variant of the AK-101. It features a 12 inch barrel and the same muzzle device as the AKS-74U, designed to help the weapon cycle.
RPK-201
Export variant of the RPK-74M. This weapon has the same features as the RPK-74M, and is chambered in 5.56 NATO.
AK-107/AK-108
AK-107
Unlike the other AK variants, the "AK" in this weapon's designation stands for "Alexandrov/Kalashnikov". It features the "Balanced Automatic Recoil System", derived from the AL-7 rifle and the AO-38 rifle; the gas from the fired cartridge moves the piston rod attached to the bolt carrier, and it also moves another piston in another gas chamber, which moves the opposite direction, reducing the effect of recoil. The cyclic rate for this weapon is significantly higher than other AKs, at 850-900 rounds per minute.
This rifle features a 3-round burst in addition to the semi-automatic and full automatic modes of fire.
AK-108
5.56 NATO variant of the AK-107, but with a more efficient and stronger material than its predecessor.
See also
References
- ↑ Section 3, Page 6, U.S. Army AK-47 manual
Sources
- Modern Firearms - Kalashnikov AK and AKM assault rifles (USSR)
- United States Army AK manual
- Wikipedia: AK