7.62x54R T46

I often see post war green tipped 7.62x54R cartridges with a distinctive stepped bullet refered to as T46. I see some sources refer to a T46M also. What exactly do these designations mean? Does 46 refer to a year or the factory that made/designed them? Thanks in advance for any nfo.

First standard Soviet tracer bullet for 7,62x54R was T-30 (military index 57-T-322). It has white colour trace at a distance 800 meters.

In 1938 this bullet was modernized replacing old tracer mixture with new one, which the trace up to 1000 meters.
The modernization was made by Plant #46 and new model of the bullet receive the number of it’s author - T-46 (index was also 57-T-322).

In early 1970-th was created new model of the tracer bullet - T-46 M (index 7T2M). New bullet has bigger lead core and smaller cap with tacer mixture. Bullet get a small step on the surface. It was made to make a trajectory of tracer bullet equal or near the same as standard ball bullet, such as LPS.

Great info. Thanks Treshkin!