After a fair amount of forming cases from other available cases, it is my opinion that the considerable re-sizing of the 303 cases caused severe work hardening of the brass that was not relieved by annealing. It takes some experience to decide when to do this. I anneal after fireforming, but sometimes it is also necessary before the reforming is completed. Care is necessary to prevent "burning" the cases. A couple of the cases also seem to show signs that "creases" formed during the process which, if true, is sure to create splits. If any more this lot of ammunition is left, I recommend pulling the bullets, dumping the charge, depriming (pop the primers) and anneal the cases before reloading them. I would have chosen original length 38-55 cases to make them from, others commonly choose 303/30-40, or 9.3x72R. The choice is for the person making the cases to make and taking the responsibility for. My choice results in short cases, others may result in splits, others may result in thick necks, others may result in use of cases needed for other longer cartridges.
Mike
Also, it should be noted that the ammo was shot and split sometime after loading and brass is subject to cracking after age hardening, we have all seen antique ammo with split necks.
Mike
Last edited by Der Ami; 05/05/25 10:26 AM.
