Charles E;678761 . . .Remember in 1957 the Frankford Arsenal skipped one draw on the match brass said:
Charles
The "problem" with the Frankford Arsenal '57 Match brass lasted only a short time and was in the primer pocket only. During WW II, all primers were crimped and sealed, which was sufficient to hold them in place, even when used in MGs. So, forming the pocket in one draw was sufficient. But when the crimp was omitted in the Match cases it was found that the fired cases often had loose pockets so they were not recommended for reloading. So, they returned to the old two draw process which made the sides of the pocket straighter and the metal more "springy". At this same time, Frankford was testing a new styphnate non-corrosive primer and the primer pocket was tailored to it.
Nothing else was done to the rest of the case, AFAIK. I have a couple of test cartridges that were made to compare the two different processes. They are specially marked and are more-or-less collectable
Ray.