The Korobov Device 3B (“прибор 3Б” in Cyrillic) experimental assault rifle with three barrels was designed in 1962 to test salvo-firing system that sought to increase hit probability. Idea behind this concept was to fire several bullets as a single salvo or a as very short, fast-cycle burst and thus achieve so called ‘shotgun effect’, where controlled dispersion of several projectiles can somewhat increase hit probability under real-life combat scenarios, compensating for minor aiming errors. Multi-barreled system was simplest and most obvious technical solution for very high theoretical rates of fire (1800 rounds/minute and up), and so designer Gennadij Korobov designed this three-barreled weapon as a test-bed for the salvo concept.
Device 3B assault rifle has three 7.62mm barrels, mounted side by side in a single cluster. There is a single breechblock that slides vertically and locks or opens all three chambers at once. The barrel cluster, along with receiver and magazine housing, are allowed to recoil inside a bullpup-type outer housing, made from stamped steel. Specially designed magazine had three compartments spaced side by side, each feeding its of barrel. Capacity of each compartment was 15 or 20 rounds. Rifle fired three-round ‘bursts” or “salvos” per single trigger pull, launching all three projectiles within 0.1 second, which is equivalent to theoretical rate of fire of 1800 rounds per minute. However, it appears that the 3B device was capable of firing only 3-round salvos, but no single shots nor continuous bursts.
Initial tests have shown that Device 3B assault rifle can offer noticeably increased hit probability ‘per trigger pull’, compared to standard AKM assault rifle, so Korobov continued his work. By 1965 he designed another three-barreled assault rifle, the TKB-059 (ТКБ-059). It follows same concept as Device 3B, but is lighter and somewhat more elegant, or, at least, less crude. It also has been tested and have shown improvements in hits probability, but no further work was done due to inherent problems associated with the concept, such as excessive recoil, inability to provide accurate single shot fire or continuous suppressive burst fire, and so on. It must be noted that multi-barreled, salvo-firing assault rifles were designed and tested in USA (during SALVO and SPIW programs) and later again in USSR, but no one realistically expected those to be fielded. Most of these weapons were test-beds and experimental designs, and Korobov Device 3B assault rifle and TKB-059 assault rifle were no exception.
|Full text name||Korobov Device 3B and TKB-059 three barrel assault rifle (USSR)|
|Caliber cartridge||7.62x39mm M43 Soviet Intermediate Cartridge|
|Overall length, mm||690|
|Weight empty, kg||3.85|
|Magazine capacity, rounds||60|
|Cyclic rate of fire, rounds/min||1800|