The bulge is intentional. Flat nosed 45/70s won’t make the corner into the magazine without it.
ETA. I see you figured that out.
What is the gain in going to the larger tenon? I can’t see the .007” per side making a huge difference strength wise. IME the chamber will bulge and the receiver will crack through the front two scope base screws and the thin web between the barrel threads and the magazine tube hole if you blow one up. They’re so thin through the front of the receiver that those holes all line up like the perforations in a check book and split them longways. I’ve seen, handled, and inspected more than a couple that had let go in this fashion and none ruptured the barrel.
Last edited by TheKid; 03/23/22.
