Due to excessive barrel wear however, it was eventually limited by an electrical trigger to a rate comparable to the Berezin UB.

Initially intended to be mounted in the defensive turrets of the Tu-4 bomber, the A-12.7 was ultimately installed only in trainer aircraft and helicopters.

After the Second World War various attempts were made to increase the rate of fire of the Berezin machine gun.

Afanasev's prototype 12.7mm machine gun was designated TKB-481 and reached an impressive rate of fire of 1,400 rounds per minute.

However, because of barrel wear problems a special electrical trigger system was introduced, that artificially reduced the rate of fire to 800 - 1,100 rounds per minute.

With this modification the barrel life increased to 4,000 rounds, however the gun no longer had any distinct advantages over the Berezin UB.

As the actuating slide moves back and forth, a traverse lug in the weapon housing is cammed into this recess to guide the chambering levers.