There’s a picture of a pivot/trunnion jig being used on the spot welder in Peter’s book (p144). That spot weld can make getting the pivot/trunnion off the tube quite difficult. The braze melts with no trouble, but that spot weld can be a problem.
Yes, that’s critical. What I found what works for me is clamping the butt in the end cap, with the cap pushed into the open position for the butt and the butt locking lugs aligned to just clear the recesses in the cap. Mind you, if you didn’t get the end cap locking ring aligned correctly on the receiver tube…For the butt especially, it is CRITICAL to align the Trunnion properly. Or the Butt wont line up with the butt holding lugs recesses. On the inside of the Return spring end cap, When opened up!....
I wonder what happened to all the Sterling tooling, jigs, etc.