How Much Crimp?

1
How much crimp is correct for straight walled cartridges? I guess this applies mostly to revolvers since loading manuals say it’s optional on 45-70 single shots and autos headspace on the case mouth.

On 357, it’s a requirement, but the instructions all give qualitative descriptions (“light” “more for heavy loads” and such).

Here are three different crimps:
37ADE822-3390-49BD-B271-C9637F953240.jpeg
Sorry it’s so big. I wanted to be able to show detail.

From left to right, it’s a Lee Loader with a few light taps of the crimping die. Middle is the Lee Hand press with the crimp backed most of the way off so it just crimped more than the bullet seating die. Last is with a half turn more crimp. Load for all three is 4.6 gr Unique under 158gr LSWC in new Starline 357 brass. All measure out to 1.590”

Enough? Too much?

Re: How Much Crimp?

7
I always crimp but usually it is a light crimp, so light it is difficult to see. If I am using the ammo in a light weight pistol or have a heavy charge I use a medium crimp. With my Lee dies a light crimp is a half turn and a medium crimp is 3/4 turn. Neither crumple the case. Bajajoaquin cases seem like a very heavy crimp. Most instructions leave a lot of room for interpetation. I hit on my formula by trial and error. Good luck with your efforts.
"Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety" Ben Franklin
Beto in wisconsin

Re: How Much Crimp?

8
bajajoaquin wrote: Tue Jun 09, 2020 6:55 pm Enough? Too much?
see if you can find someone local with some experience to walk you through the process. i did that with a member here, adjusted the dies, loaded a couple of rounds to demonstrate, then used him as slave labor while he asked questions. also sometimes it's helpful to use a storebought round to get everything adjusted to spec. after you're done, THEN drink beer. :beer2:
i'm retired. what's your excuse?

Re: How Much Crimp?

9
A little heavy but won't hurt anything. The worst that will happen is that you stress the case mouth. I would still send, but next time maybe 20% less if you're shooting a lever gun or revolver, 30% if you're shooting a single shot

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