The AO-34 is a Soviet prototype bullpup assault rifle.
Designed in 1965 by G.P. Petrovpavlov, the AO-34 has a recoil-reducing or recoil-balancing device. The weapon was of the bullpup layout. The weapon was designed in 1965 and tested, but was not adopted likely due to the complicated mechanism.
The AO-34 is a bullpup rifle with what appears to be a vibratory recoil reduction system which is based on inertial operation. The weapon was buffered by a series of springs to help reduce recoil; this system apparently worked, with trial reports saying that field tests showed an effectiveness increase of 1.5 times when shooting from odd positions.