Crimping and Setback

Maybe full length size before loading powder and seating  bullet.
Case tension should prevent setback with those crimp dimensions

james r chapman wrote:Maybe full length size before loading powder and seating  bullet.
Case tension should prevent setback with those crimp dimensions

My RCBS Carbide Resizer is set to touch the shell holder and sized cases seem to be spec. 
I’m wondering if my seater is the problem. It’s an old RCBS die from 1980. The box says 45 ACP, but looking inside the seat die, I can see a clear ledge. Maybe they only made roll crimp dies for the 45 ACP back then. I’m also using range brass, so various head stamps. I’ve noticed after resizing, case length can vary by .002” or .003”. That being the case, if I’m using a roll crimp die (set to taper crimp), wouldn’t that change my taper diameter by several thousands, based upon case length?

j_unzicker wrote:

james r chapman wrote:Maybe full length size before loading powder and seating  bullet.
Case tension should prevent setback with those crimp dimensions

My RCBS Carbide Resizer is set to touch the shell holder and sized cases seem to be spec. 
I’m wondering if my seater is the problem. It’s an old RCBS die from 1980. The box says 45 ACP, but looking inside the seat die, I can see a clear ledge. Maybe they only made roll crimp dies for the 45 ACP back then. I’m also using range brass, so various head stamps. I’ve noticed after resizing, case length can vary by .002” or .003”. That being the case, if I’m using a roll crimp die (set to taper crimp), wouldn’t that change my taper diameter by several thousands, based upon case length?

I'd change to a dedicated taper crimp die and crimp as the final separate step to your reloading process.

Your COAL variation is normal and expected as we aren't seating off the bullet tip, and the ogive (where we seat with JHPs or FMJs) to tip distance will naturally vary between bullets even of fine quality within the same lot & box.

No need to crimp more than 0.470" with jacketed to my knowledge. (Lead is different). You don't need to crimp so much to be deforming your 230gr Zero JHPs, certainly not to an amount you can feel on a pulled bullet. I've loaded quite a few of those with success.

With mixed brass and small enough sample size this could all come down to brass rather than crimp variations. A taper crimp should only touch the forward edge of the case and not compromise the bearing surface or friction and waist neck tension from an adequately sized case I'd think.