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.
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.
|This article first appeared in Small Arms Review V23N1 (January 2019)|
and was posted online on November 16, 2018