By Lynndon Schooler

Peter Andreevich Tkachev was a small arms engineer for TsNIITochMash, the Central Scientific Research Institute for Precision Machine Engineering, located in Klimovsk about 50 miles to the South of Moscow. A recipient of the Hero of Socialist Labor medal, he is the designer best known for creating the “BARS” Balanced Automatic Recoil System on the prototype AO-38 construction, which is his most enduring design still used today in mainstream Russian small arms production; most famously in the AK-107 and civilian Saiga MK107/SR-1.

AO-63 History

The city of Klimovsk is a small urban center. For much of its Soviet history, and to a lesser extent today, the military and engineering sites of Klimovsk were “closed” installations. Soldiers and scientists lived in on-property dormitories, concrete apartment blocks if married, or if they were lucky and in a position of command, they commuted from Moscow by an electric olive drab commuter transport train. The highest-ranking KGB and authorities naturally had a driver bring them to TsNIITochMash. Either way, work materials were never allowed to leave grounds, and the men and women who worked there for the progress and mutual defense of their country saw virtually no international recognition for their labors as seen by the hotshots in Tula or Izhevsk. Partially because of the cloak and dagger secrecy and partially because of a lack of widespread success, little is known about the designer Peter Andreevich Tkachev working alongside Sergei Gavrilovich Simonov, designer of the SKS. Before Simonov’s death in 1986, the pair finished constructing the AO-63 prototype—one of the most creative but ill-fated small arms never put into production during the Cold War.

In 1981, the Ministers of the Soviet Union called for a program to build a replacement for the AK-74. It would seek a new assault rifle with increased effectiveness in automatic and burst fire. The objective was to create a lightweight design that would increase hit probability by 1.5 to 2.0 times. The project was code-named “Abakan” after a river in the Republic of Khakassia. The program was nearly identical to sporadic U.S. efforts since WWII and later the U.S. Advanced Combat Rifle Program. Eventually, it would reach the same conclusion—“what we have is good enough, and only marginal improvement is not worth the production cost.” But at the time, it was an engineering challenge, if not a mandate, to be addressed by virtually every design shop across the USSR, including Tkachev at TsNIITochMash.

In 1984, the AO-63 development began. Tkachev answered the need for increased hit probability in a burst with a brutally simple answer. In the absence of new ammunition with duplex rounds, he would make a double-barrel rifle that could fire two rounds almost simultaneously. The most striking feature visually is its two barrels in a side-by-side configuration. Out of necessity, both barrels had their own gas system. The gun operated with two pistons, two bolts, two hammers, a dual recoil spring assembly and essentially two of everything in the core function of a rifle. Coming in at almost 8 pounds, the gun is remarkably light when its construction concept is kept in mind.

The rifle has a unique fire control group with the selector on the right side, capable of safe, semi, burst and automatic fire. In burst mode, the rifle fires the first two shots at one of the fastest rates of fire ever documented in an assault rifle—6000 rpm or one millisecond between shots. Potentially, the gun could fire simultaneously, but the delay in fire is deliberate to counteract any negative effect on ballistics and a near constant recoil impulse. When on automatic fire, the gun has a short “fast-auto” and long “slow-auto,” meaning that the first two shots will be both barrels at the near instant rate of fire, but continued trigger pressure will switch fire to only the right barrel, which will shoot at 850 rpms in continuous fire. This makes the right side the predominant barrel.

The fire control group has, interestingly, no hammer springs but rather strut springs and strut arms that are connected to the hammers. Each bolt operates independently. The charging handle is attached to the primary right carrier. There is a short linkage bar connecting each carrier at the rear, and a sleeve on the right carrier supporting the left carrier rod allows for reciprocating movement. Each carrier has a “stem” that each bolt rotates over on a cam pin. The right carrier has a separate rod which is attached to the charging handle. The spring on the charging handle rod appears to be a “momentum spring,” allowing for rearward movement of the handle before the bolts start to unlock. It likely assists in reliability and ensures equal force distributed across both bolts. When pulling back on the bolt, the linkage bar pulls the left carrier rearward unlocking the left bolt. Each piston has a support guide behind the piston head to support reciprocating movement in the gas tubes. The locking lugs are 1 inch back from the bolt face. The trigger is a double hook to grab both hammers. Note there are only one sear trip and two disconnectors. When disassembled, the selector mechanism is difficult to see because it is covered by a housing.

The magazine is always a critical part, if not the most critical part, in a firearm’s reliability. Despite the redundancy of the gun, the AO-63 fires from technically a single magazine but keeps up with the impressive rate of fire. The prototype magazine appears to be a rough steel fabrication with two chambers. The left action feeds from one 15-round stack, while the right feeds from a 30-round stack. The magazine is technically a quad-stack, with a 45-round capacity.

The Abakan Trials

Though this is only speculation, the gun was likely dropped for its high production cost and for a lack of practicality. The Abakan trials were won in 1994 by Gennadiy Nikonov at Izhmash, with his AN-94—a less accurate, heavier and more complex design. In a side-by-side comparison of examples that I have personally examined, the AO-63 is easier to clear malfunctions and maintain than the AN-94. The AN-94’s victory was underwhelming. Rather than replacing the AK-74, as was the intention of the Abakan trials, the AN-94 saw extremely limited use under the GRAU adoption designation 6P33. The collapse of the Soviet Union was likely the last nail in the coffin of the Abakan’s success, because it essentially froze military industries as the country weathered economic and social collapse. But just as likely, the culprit was the hard truth that the AN-94’s complexity and expense outweighed any advantage that its high rate of fire offered. Russian operators in highly specialized tasks are still effective with simpler Kalashnikov-based designs. Though failing to be a firearms technology breakthrough, the AN-94 carries the title of “the last Soviet designed assault rifle.”

I would like to thank the Kalashnikov Museum in Izhevsk Udmurtia for letting me inspect, disassemble and document this rifle in 2017; I regret not getting more quality detailed photographs to publish.

Despite its ability of working with a new 5.45 cartridge, it was evident the AK74 could not improve accuracy to the extent the military initially wanted. The reason why they agreed to a compromise was the fact that AK74 appeared to be the cheapest way of introducing a new round. The Army would not have to change existing field repair workshops and the inventory of spare parts. They would not have to re-train soldiers – the technique of firing the AK74 was to a great extent similar to that of AKM. The design of the new weapon was also similar to the one soldiers were used to.

The degree of parts commonality of AKM and AK74 was a strong factor in favor of the Kalashnikov’s development. In this case, to change from one model to another, the industry would not require large investments, which the Soviet economy could not afford so easily any more.

Soon after the war in Afghanistan broke out in 1979, the Ministry of Defense once again raised the issue of developing a novel small arm, more accurate and hence more effective, in caliber 5.45x39mm. GRAU, in cooperation with TSNII TOCHMASH – a most influential military-technical research institution, outlined several probable plans for a future weapon; balanced automatics and the so-called principle of a Blowback Shifted Pulse being among them. The declared design contest was given the type name of “Abakan”. The number of participating design groups was 12. Izhmash had two teams in the contest: one had Victor Kalashnikov as a project engineer, while Gennadiy Nikonov headed the second one.

Several competitors, among them G. A. Korobov of Tula, V. M. Kalashnikov from Izhevsk and A.S. Konstantinov from the city of Kovrov, the Vladimir District, produced three assault rifles based on the balanced automatic mechanics.

Nikonov, on the other hand, gave his preference to the delayed (shifted) blowback impulse or BBSP – blowback shifted pulse. Nikonov is a serious and knowledgeable engineer, who perhaps has a better command of subtleties of fire arms mechanics than many in the field. Nikonov believes that “balanced mechanics” is limited to only relatively small calibers and ammunition with relatively low energies. In any event, balanced mechanics does not eliminate the recoil. It simply modifies the kick, dividing the impulse into several sub-phases. In the full-auto mode, a weapon with balanced mechanics alters the recoil impulse and makes it look graphically more like an impulse of a single shot firearm.

In the “Abakan” project Nikonov was able to look into the future of small arms. Like his prominent predecessors Vassiliy Degtyaryov and Mikhail Kalashnikov, Gennadiy Nikonov realized that an ideal weapon should be capable of modernization into a full spectrum of combat small arms: machine pistol, assault rifle and machine gun. The latter, with a heavier cartridge, if it had a balanced mechanism, would not work as well as the weapon with a smaller round. He also understood that even the BBSP is not a panacea and does not eliminate the recoil as such at all. His partner, if we may say so, was the factor of time. In a high rate of 1,800 rpm, the gun fires two cartridges, the barrel plus the receiver with the bolt group performs a rearward motion. With the two bullets heading down range towards their target, the moment when the gun slams against the operator’s shoulder is yet to come! When the kick does come, it does not affect the accuracy. Unlike the balanced mechanics, this principle will provide high effectiveness of fire with practically all types of small arms.

On the way to designing a final version of his weapon Nikonov produced more than 20 intermediate prototypes. We were able to discover 12 of them – that’s all that is left.

Prototype 1. NA-2.

Year of manufacture: 1979
Caliber: 5.45×39 mm
Weight, empty and without magazine: 3.88 kg
Overall length: 755 mm
Modes of fire:
– Semiautomatic
– Burst of three rounds in high rate of 1,800 rpm
– Variable from high rate of 1,800 rpm to 600 rpm.

From the very beginning of his participation in project “Abakan,” Nikonov made the weapon totally different from the Soviet issue AK-74M assault rifle. It is a short submachine gun in a bullpup configuration. When asked, why he decided to create a bullpup, Nikonov describes his choice as a “vanguardism of youth” as well as a desire to show off. He also added that like Mikhail Kalashnikov’s AK47 that has certain resemblance to the German MP43 and MP44 submachine guns, his NA-2 rifle was created under the influences of the same models.

The steel buttplate is retained in place with the locking lever located on top the rear part of the stock. To fieldstrip the weapon, open the top lever and swing the buttplate to open. The entire integrated firing mechanism comes out from the carrier-stock.

Prototype 2. NA-4.

Year of manufacture: 1981
Caliber: 5.45×39 mm
Weight, empty and without magazine: 3.83 kg
Overall length: 750 mm
Barrel length: 415 mm
Modes of fire:
– Semiautomatic
– Burst of three rounds in high rate of 1,800 rpm
– Variable from high rate of 1,800 rpm to 600 rpm.

The next prototype in this series also has a bullpup configuration.

The barrel is made from stainless steel. Again, the front portion of the barrel features several drilled side holes, which perform the role of a muzzle brake. The sights are similar to those of the NA-2 model. The sheet metal, spot welded receiver is that of the lafette type, which functions as an integrated slide for the firing unit – a barrel plus receiver plus bolt group assembly.

The front sight is borrowed from the AK system, taken along with the standard 30-round plastic box-type two-row detachable magazine and its locking latch. That is all there is in common between the two constructions. The dioptrical rear sight with a sliding tangent is placed on top the carrying handle, which is located above the front of the receiver.

The barrel protrudes from the carrier-stock and has side openings for a muzzle brake. Under the front part of the barrel there are two bayonet mounting lugs. The pistol grip and the handguard are made of laminated plywood. For greater ergonomic comfort, the fire mode selector is located on the right side above the pistol grip. As shown in photo, the selector moves anti-clockwise and has four positions: Safe, Semiautomatic, Three-shot burst, Fully automatic.

Prototype 3. AS-1.

Year of manufacture: 1982
Caliber: 5.45 mm
Weight, empty and without magazine: 4.18 kg
Overall length, with buttstock unfolded: 980 mm
Modes of fire:
– Semiautomatic
– Burst of three rounds in high rate of 1,800 rpm
– Variable from high rate of 1,800 rpm to 600 rpm.

At this point Nikonov abandons the bullpup configuration. In our private conversations he explained that after extensive tests of the two previous modifications, he found that the bullpup creates serious discomfort to a shooter – there are too many fumes in the area right in front of the shooter’s face. Combustion gases sometimes are so thick that an operator has to drop the gun and run for fresh air. In addition, the bullpup poses a problem for a left-handed soldier. Empty cases being ejected and evacuated through an opening under the top cover on the right side come flying in the immediate environment in front of the shooter’s face, distracting his or her attention from aiming. According to Nikonov a bullpup is good for Special Forces, not the Army.

AS-1 has a short L-shaped folding buttstock made from laminated plywood. Its pad is made from rubber. The stock attaches to the receiver by means of an original hinge. The receiver and upper handguard are manufactured from stamped and spot welded sheet steel and coated with black phosphate. The laminated foregrip is rather long compared with the AK series. The barrel in fact is almost completely covered with a handguard. Only a short portion of it with a flash suppressor comes out from the stock to accommodate a bayonet by means of bayonet mounting lugs located under the muzzle.

It might be of interest to note the reverse location of a peep-type rear sight. Such a position looks quite logical from the ergonomics point of view – the buttstock is too short to provide sufficient space for an aiming operator. The front sight is also Nikonov’s original.

Prototype 4. AS (OA-222).

Year of manufacture: 1984
Caliber: 5.45×39 mm
Weight, empty and without magazine: 3.18 kg
Overall length, with extended stock: 940 mm
Modes of fire:
– Semiautomatic
– Burst of three rounds in high rate of 1,800 rpm
– Variable from high rate of 1,800 rpm to 600 rpm.

It is the most unusual of the Nikonov’s earlier prototypes. At first glance it produces an impression of being totally asymmetrical. Rather short, it is not a bullpup yet and features a folding buttstock borrowed from the AK74S. The sliding firing unit is located inside the carrier-stock made of stamped and welded sheet steel. The handguard is made of laminated wood for better heat insulation. The sights are similar to those of the previous AS-1 model. It is the only model which has no bayonet mounting lugs. In our opinion, a bayonet is a relic of the “positional war”. A good multi-functional dagger or a knife would be of a greater use for a soldier in modern warfare. Does AS (OA-222) mean that Nikonov tried to change the attitude of the military towards a bayonet?

The magazine is located at an angle in regard to the receiver like in the later “Abakan” versions for the purpose of providing additional room for the return spring. Very lightweight, AS (OA-222) provides exceptional comfort during firing.

Prototype 5. AS (VS-229).

Year of manufacture: 1985
Caliber: 5.45×39 mm
Weight, empty and without magazine: 3.90 kg
Overall length, with buttstock extended: 992 mm
Modes of fire:
– Semiautomatic
– Burst of three rounds in high rate of 1,800 rpm
– Variable from high rate of 1,800 rpm to 600 rpm.

By way of experimenting, Nikonov manufactured the integrated carrier stock of AS (VS-229) assault rifle from the aluminum alloy. This model made it possible to carry out extensive tests on the durability of such a construction. Some of the later prototypes feature carrier-stocks made of a similar material. Like in the above versions, AS (VS-229) has a moving magazine and a 3-round burst option. The under-barrel rod is made available to provide additional support for a bayonet.

Prototype 6. AS (PU-192).

Year of manufacture: 1986
Caliber: 5.45 mm
Weight, empty and without magazine: 4.07 kg
Overall length, with stock extended: 992 mm
Modes of fire:
– Semiautomatic
– Burst of three rounds in high rate of 1,800 rpm
– Variable from high rate of 1,800 rpm to 600 rpm.

This is the last modification with a moving magazine and a 3-round burst fire mode. From this prototype on Nikonov approaches the final shape of AN-94. It has an under-barrel extension rod. The flash suppressor features a roller, which travels along the rod thus providing additional support for the sliding barrel-and-receiver assembly.

Looking at the polyamide handguard one can easily notice that it has a vertical segment that prevents the operator’s hand from interfering with the sliding motion of the magazine during firing. The unusual mechanism located under the handguard has a dual function: (a) folding solid steel monopod and (b) magazine protector. It folds rearward. The standard 30-round box-type magazine cannot be attached without unfolding this mechanism. Both the magazine and the operator’s hand are protected against slamming the walls and the firing port in an APC. The AS (PU-192) rifle features a laminated folding stock that folds to the right. The fire mode selector is located under the receiver right behind the magazine.

Prototype 7. ASM (OK-158).

Year of manufacture: 1986
Caliber: 5.45 mm
Weight, empty and without magazine: 4.26 kg
Overall length: 1,017 mm
Modes of fire:
– Semiautomatic
– Burst of two rounds in high rate of 1,800 rpm
– Variable from high rate of 1,800 rpm to 600 rpm.

The rifle features a non-folding laminated buttstock, a plastic pistol grip and a handguard. The integrated carrier-stock is made from aluminum alloy, while the handguard is manufactured from a thermosetting synthetic material. A most striking detail of the rifle’s exterior is an impressive muzzle device, consisting of an integrated front sight and an adjustable two-chambered flash suppressor. The suppressor has three vertical slots on each side. The sliding firing unit is incorporated with the barrel and has an additional front support. The plastic cap in the rear of the handguard indicates that this model features an internal spring buffer, which reduces recoil pulse.

Prototype 8. ASM (MA-49).

Year of manufacture: 1988
Caliber: 5.45 mm
Weight, empty and without magazine: 4.21 kg
Overall length: 1,000 mm
Modes of fire:
– Semiautomatic
– Burst of two rounds in high rate of 1,800 rpm
– Variable from high rate of 1,800 rpm to 600 rpm.

This weapon has a modified adjustable flash suppressor, a guiding extension rod, two internal buffers, an integrated carrier-stock made from aluminum alloy and a plastic handguard. On top of the rear side of the bolt cover there is a non-detachable optic scope. At the time this prototype was designed, the military sent instructions that from that time on, all small arms had to have optic scopes, not iron sights. Later developments revealed that such an approach held no water. In a number of situations the lenses were damaged in the operation and the weapon could not be used since alternative sights were not available. Later developments had a possibility of using both iron open sights as well as optic devices of daytime and night vision types. The laminated non-folding buttstock is integrated with a pistol grip. The bayonet attaches to the right side of the barrel, in a horizontal position.

Prototype 9. ASM (MA-50).

Year of manufacture: 1988
Caliber: 5.45×39 mm
Weight, empty and without magazine: 4.26 kg
Overall length: 1,007 mm
Modes of fire:
– Semiautomatic
– Burst of two rounds in high rate of 1,800 rpm
– Variable from high rate of 1,800 rpm to 600 rpm.

The ASM (MA-50) is in principle a version similar to ASM (MA-49). The differences are as follows:
– The integrated fixed scope is replaced with an open rear iron sight;
– The post-type front sight with protective ears is located on top the front part of the carrier-stock;
– The barrel guiding rod is additionally equipped with an under-barrel grenade launcher mount;
– The usual base plate for a scope mount is located on the left side of receiver.

Prototype 10. ASM (PA-33).

Year of manufacture: 1989
Caliber: 5.45×39 mm
Weight, empty and without magazine: 3.75 kg
Overall length: 946 mm
Modes of fire:
– Semiautomatic
– Burst of two rounds in high rate of 1,800 rpm
– Variable from high rate of 1,800 rpm to 600 rpm.

This version is another closer step towards the present shape of the AN-94. It is the first modification that features a novel asterisk-shaped rotary peep sight. The AK-type front sight again is located on the barrel. The flash suppressor is very laconic and has two side openings at the muzzle. The bayonet lug is placed at an angle on the front left side of the barrel. The angle is calculated in such a manner that the bayonet never interferes with the line of aiming. The barrel slides along the guiding rail of the stock extension rod, which looks almost exactly like the one in the AN-94. The lever located on the right rear side of the carrier-stock is a release mechanism for a detachable trigger mechanism. The knob located above the pistol grip behind the receiver is a retainer for the above lever.

Prototype 11. 6P33.

Year of manufacture: 1991
Caliber: 5.45×39 mm
Weight, empty and without magazine: 3.80 kg
Overall length:
– with buttstock extended: 943 mm
– with buttstock folded: 728 mm
Length of barrel: 405 mm
Barrel: chrome plated, 4 RH rifling of one turn in 195 mm.
Modes of fire: – Semiautomatic
– Burst of two rounds in high rate of 1,800 rpm
– Variable from high rate of 1,800 rpm to 600 rpm.

The 6P33 is in fact the prototype that passed all technical and field-tests and received the approval as the assault rifle qualified for adoption as an issue firearm of the Army. Nikonov won the competition! In 1992 Nikonov received personal congratulations from Boris Yeltsin. The Governmental cable came to the Izhmash’s Department 1, the service that handles classified materials, saying that the President had instructed the Government to allocate the funds required for prompt transfer of production at IZHMASH from AK to Abakan. The Army was still in hesitation whether to give this weapon a full “GO”. The AN-94 was a really novel model. In terms of production, it needed much more sophisticated equipment and technology than the current AK-100 series. The question was how many rifles per year the military would want to buy? Will it be feasible to invest substantial funds and order only a limited number of rifles? Meanwhile, Nikonov and his team kept on working on the weapon, giving it “a finishing shine.” For the most part the work on the weapon was dedicated to adapting its construction to the requirements of mass production. It took him three more years to get the approval from the Russian military. In 1994 the GRAU registered Nikonov’s “Abakan” as an issue assault rifle under the new type-name of “AN-94”.

The design of the guiding slide of the stock extension rod deserves special attention. Moving back after the shot is delivered, the barrel is invariably subject to the phenomenon which is known as “barrel climb”. As one of the means of reducing the climb the slide has a rearward slope. The slope in conjunction with a recoiling barrel creates a dynamic moment, which pushes the whole construction downwards thus reducing the barrel jump.

As one can see it from the above photos, Nikonov changed configurations and envelopes from a compact bullpup to a full-sized rifle. The Nikonov “Abakan” had different stocks made from spot welded sheet metal, laminated wood and reinforced thermosetting polyamide. He was extensively experimenting with sights, pistol grips, buttstocks, scopes and accessories. His first versions had a mode of 3-round bursts, while later weapons were changed to a 2-round burst possibility. In the case of the modifications with a 3-round burst, the rifles had a rather unusual feature – a moving magazine. In fact, the magazine is a typical 30-round construction, made of plastic. What’s unusual is that it moves. Later, under pressure from the Army, Nikonov made a fixed magazine and reduced short bursts from 3 to 2 rounds. Soldiers thought that a sliding magazine creates certain discomfort during firing. Also, they said, with a 3-round burst in the high rate of fire ammunition runs out quickly. Thirdly, two bullets fired in a standing position with accuracy 13 (!) times better than that of the Russian issue AK74M assault rifle are more than enough to destroy a target. Why waste the third round then?

It is important to note that the change from a three-round burst – a concept that the conservative Army inspectors and representatives involved in the project were so stuck on, to two rounds is a sure recognition of the weapon’s extremely high effectiveness. According to the late Dr. David Bolotin, author of numerous books on the Russian small arms and an authority in this field, the entire effectiveness of the AN-94 is two-fold greater than that of the Russian AK74 and 1.5 times more effective than the American M16A2. At the same time there are several basic features that remained intact in all modifications of the gun. These are as follows: – 1,800 rounds per minute in a high rate of fire, 600 rounds per minute in a standard rate, Blowback shifted pulse, Sliding barrel assembly (firing unit).

It would be fair to say that AN-94 is a complete departure from the existing AK-type scheme of a small arm. It wouldn’t be less fair to say that the statement, which we came across in some sources regarding Nikonov as one of the Kalashnikov’s students, is absolutely incorrect. Nikonov says he is rather a student of Evgeniy Dragunov, inventor of the SVD rifle, and Azariy Nesterov – a key arms designer at IZHMASH and a leading engineer in several experimental projects. These two persons produced a great influence on Gennadiy Nikonov in terms of professionalism and team leadership.