Billy Pyle has had "gas trap" shooters at his personal range in Texas, every year they have a gas trap match. He told me they use LC 69 30 cal M2 ball. They
change out the firing pins to the later type and replace the keystone springs. All gas trap rifles are original not new reproduction. There is even a special gage
used to make sure the muzzle plug is in correct alignment with the bore. I understand they had another original gas trap shooter that just surfaced
