I am not new to reloading long rifle but am new to 45 acp. I understand the 45 head spaces off of the mouth, the manual calls out a 0.4730 in.for the mouth of the case. After expanding, seating and crimping ( depending on the amount of crimp ) I mic out at 0.4600 in (Heavy crimp) too 0.4720 in. (light crimp)
Is there a minimum call out for the finished round at the mouth of the case after crimping?
As many millions of pistols have been made in .45 acp from high end competition guns to bargain basement Zamak slide versions, the expected chamber dimensions will vary quite a bit. I taper crimp my .45 acp rounds just enough to return the mouth to parallel and screw in the crimp die about another 1/4 turn. I do not worry much about exact dimensions of the crimped surface. I just want to eliminate the belled end and hold the bullet firmly. The .45 is very forgiving of ammo unless you are shooting an ultra tight STI comp gun.
Yup, on a 45 acp pistol, a nice firm taper crimp is the way to go! No matter what the pistol or case OAL, I always look for slight evidence of brass, 'fairy dust' on my finished rounds. If I'm getting it, then, I know the crimp die setting AND the case OAL are a perfect match for each other.