82nd
Trooper.
I also watched another friend, Gerrold Pheffer, fit up new barrels ( a couple were mine), but to O/Us. He always fit the barrels to the frame first, before cutting the hook and fitting the hinge pin. This way he got good contact with the breach face, without having to worry about the hook. He then fit the locking lug( using a dummy locking wedge) and only after that marked and cut the hook and scraped it to fit the pin last ( except for filing to match the frame).
Mike