My Ballaster-Molina 45 has always give me problems with cast. Originally I sized to 452 because that's the only 45 sizer I had. The gun would only return to battery if the boolit was seated so deep in the case that the ogive was right at the case mouth. Today I got my new 451 sizer die, ran a handful through it and started loading. First one I set OAL to 1.250 and tried to chamber it. No go!
It appears that a boolit could be no bigger than 450 at the mouth of the case. When I get it deep enough to chamber the rifling marks go all the way to the case mouth.
My question is can I throat this rifling out to give me .020/.030 of freebore without messing up my head space or am I better off to try to find a different mold design. My primary mold for ACP is the Lee 452-228 1R. Tonight I sized some 452-424 HP weighing 240 grs and could get them to chamber with about .015 of the first driving band outside the case with an OAL 1.240. It got dark on me so can't test run them until morning.