TAPER CRIMP vs ROLL CRIMP - What do I use?

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I’ve been reading everything I could find regarding the use of a taper crimp vs a roll crimp for handgun ammunition with great interest because it’s an issue I have to resolve very soon.

I just bought a Dillon XL650 with every bell and whistle they make for it. I also got a set of Dillon dies for all calibers I’ll be loading. Those calibers are .38 Spl, .357 Mag, .45 ACP, 9mm, and .45 Long Colt.

Now if I am correctly interpreting “most” of what I’m reading, the majority of people loading for handguns feel that the taper crimp is best for semi-auto handgun loads such as the 9mm and the .45 ACP because it works best at keeping the bullet from being shoved back into the case on the way up the ramp. On the other hand the roll crimp is apparently best for revolver loads such as the .38 Spl, .357 Mag, and .45 Long Colt because it prevents the bullet from advancing forward in the case under recoil (like a kinetic bullet puller) and thus locking up the revolver’s cylinder. Apparently factory ammunition is loaded using a taper crimp for semi-auto ammunition and a roll crimp for revolver ammunition. At least so I am told.

So first of all, would most of you agree that a taper crimp for semi-auto handgun ammo and a roll crimp for revolver ammo seems to be the best way to go?

Secondly, I’m assuming in either case I can still use my stock Dillon carbide sizing and seating dies, but for the revolver ammo I’m going to have to purchase a different crimping die

That being the case, who makes the “best” crimping die for a rolled crimp? And is it wise to buy just the crimping die, or should I buy the whole set?

I’m told Redding, for example, makes some of the very best dies available. Could I get just a Redding crimping die for each revolver caliber – or should I buy the whole Redding set for those calibers I want to use a rolled crimp on?

I’d appreciate hearing what other hand loaders are using in their progressive presses when loading for revolver and/or semi-auto.

Thanks for sharing your thoughts and knowledge.
 
The reason crimps need to be done so very cautiously with rimless cartridges like the 9 x 19mm and the .45 ACP is not so much to keep the bullet in place as it is due to the fact that such cartridges headspace on the forward edge of the case. Put too much of any kind of crimp on it and it can get pushed too far into the chamber, beyond the effective reach of the firing pin.

The dies should have come with instructions. Suggest that's a good place to start reading.
 
Yes, taper crimp 45ACP, 9mm and any that headspace on the case mouth. Roll crimp those that headspace on the rim.
A roll crimp on a case that headspaces on the case mouth could lead to, a failure to fire or unsafe pressures if the crimp binds in the bore. KD
 
Mine weren't. Buy a separate taper crimp die for .45ACP and 9mm. You can use your typical seating die for roll crimping revolver rounds, so the bullet seats as the crimp is rolled into the case mouth. Slicker'n... t.

With a taper crimp, it is necessary to crimp enough that the bullet does not jam back into the case while the cartridge is going for that wild ride from magazine to chamber. Since the two semi-auto's mentioned both headspace on the case mouth, it is important to not shorten the apparent case length but rolling the very end of case inward. Either the case, pushed into the barrel past the chamber will attempt to swage the bullet, incresing pressures, or the cse may push forward at firing pin impact, and fail to ignite the primer. The former is very unpleasant, the latter a darned nuisance on the range.

The roll crimp on a rimmed revolver cartridge serves not just to keep the bullet from being pulled by successive recoil, but also provides (in cases of consistent length) a means to ensure consistent bullet pull, resulting in consistent powder burn curves, velocities, and better accuracy.
 
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