Very hard bullets also allow some gas blow-by, since they don't obturate
("bump up") as the expanding powder kicks them in the rear end.
An abdominal fat graft was used to obturate
the dural defect.
45-60, is the bottleneck cases more fully obturate
in the chamber and eliminates black powder fouling from flowing back into the action.
1-3) The conventional solution to this problem has been to obturate
this area with a palatal prosthesis.
Of the loads, the smokeless didn't obturate
the well which isn't surprising and the cases came out with black smudges at the mouth.