Run one of then hard to chamber cases up the size die with the die turned down some more try chambering again, if you have to turn die down, do it again. Don't go by the instructions on these dies that say turn die down until contact with shell holder. Some times you have to turn it down until it makes solid contact through the cycle past cam-over. Machine gun brass will fatten out again when you pull it out of the die, try raising and lowering the case a few times. You'll get er.
Last edited by doubleDs55; 06/10/21.
