riginal year 1940 design was BS -
Synchronized by Berezin, Berezina Synkhronny; This prototype was developed into whole family of heavy machineguns:
UB - multipurpose by Berezin, Universal'ny Berezina;
UBS - synchronized, Synkhronny;
UBK - wing mounted, Kryl'evoj;
UBT - or turret, Turel'nij;
Army field tests of BS were conducted in January-February 1941. First 6
BS were installed on I-16 and I-153.
Some complications with reloading, requiring serious efforts, were revealed and fixed quickly.
standard - Black/Yellow
tracers - Violet-Red
incendiary - Black/Red