a good friend asked me to reseal his 77a he'd just got and it was apparent that at some point in it's life a numb nutz had worked on it
what they intended to do to the barrel band i don't know

first stage a bit of 1"x1/2" flat drilled for the barrel then the plug and reamed with an adjustable one as the plug is a fraction ove 7/16"

after loads of milling sanding and polishing i pressed it on and did a test fit