7.62x45 "50 Z"

May this be the 1st headstamp considering the year of 1950?

Hi sksvlad!
This is the first year (1950) of production still experimental sample of 7,62x45. His base dimensions are identical with other common Czechoslovakian samples of M.52 cartridges. All samples before 1950 were thinner (case + bullet) and they exists in two models - “Z 46” from year 1946 and “Z47 (or 49)” from years 1947,48 and 49.
From year 1950 is known only one headstamp “Z 50” (2x180°) and from year 1951 are known samples from the same factory “SB” with new code “bxn” (4x90°) and samples from “PS” factory with geometrical code (4x90°).
In 1951 was cartridge 7,62 x 45 officialy approved and estabilished in army as “vz.52” (mod. 52) for rifle M.52 and MG M.52.