Crimping

[BIKER13]

Is crimping for a rifle cartridge vs a pistol cartridge different? Thanks for any info.

 

[Chuckdog]

Yes and no. There's basically two types of crimps, with variants of each. A rimless cartridge like the 9mm 40 S&W and 45ACP all headspace on the case mouth and require a taper crimp. A taper crimp kinda just squeezes the case wall to near straight after bullet seating. To much crimp and the case will go to far into the chamber and not fire. To little crimp and the round probably won't chamber to full battery. A revolver cartridge such as the 38/357, 44mag 45 colt, ect, use a roll crimp. A magnum load using a healthy dose of slow burning powder requires a heavy roll crimp for consistent start pressures and to ensure the other rounds in the cylinder don't shoot loose and cause the cylinder to lock. Most handloaders don't crimp bottleneck rifle cartridges, as the neck tension is sufficient to hold the bullet in place. Ammo that's going to be banged around alot or some heavy calibers do require a crimp. You can choose the type of crimp with different dies. If I'm loading for the an AR or similar rifle, I sometimes use a Lee factory crimp die. It uses a collet to squeeze the case just at the lead edge. Most none belted bottleneck cartridges headspace on the shoulder, so crimp isn't critical for headspace. There may be others that just don't come to mind now, but that's about it. Hope this helps, Chuckdog.

 

[TBurnham]

Yup, what he said. I crimp pistol rounds but I do not rifle rounds. BUT I do not shoot large caliber rounds in rifles.

 

[BIKER13]

Yup, what he said. I crimp pistol rounds but I do not rifle rounds. BUT I do not shoot large caliber rounds in rifles.

Thanks I won't shoot the loads the guy loaded until I have someone look at them.