Usually the decapping rod will ride up, to strip the thread it must have be really tightened, also suspect you have broken the decapping pin.
There is a lot of South African mil fmj ammo that is hot, meant for machine guns, a mate had heaps of it, don’t shoot well , anyway it is Berdan primed. Came across 556 mil ammo recently the primers were full circle heavily crimped, some came out, a lot I binned.
Bookmarks