Interesting how close I got by eyeballing the chamber and using a caliper before the casting.
The cartridge's rim is .500" (actually it is .510 on the casting)
The base of the cartidge after the rim is about .434" wide. (actually it is .438)
5/8" into the chamber, the cartridge is about .415" wide. (it is indeed .415")
At 2.3" into the chamber, there is a constriction that is either a really tiny shoulder or it is the lams, I can't tell. (actually 2.285)
The bore at muzzle is measuring .316 to .325 depending how I measure but this is a fuzzy number. (bore past chamber is actually .323)
Considering how hard it was to make a simple chamber cast, I don't think I'll try that again. Basic measurements with a caliper seemed close enough.
