Crimp

[Big Guy]

What is the correct way to measure crimp?

[JThompson]

What is the correct way to measure crimp?

Hello BG... I have never measured a crimp loading 9mm. I bell my cases as little as possible then i adjust the crimp to roll the bell out and nothing more. The taper shape of the 9mm case is such that I have never had any set back issues and thus I do not crimp. Crimping can cause all sorts of problem including bullets tumbling. I find no use for it in 9mm....

I'm sure everyone will have their own opinions on the matter and noone taught me anything in the regard, it's what I have found loading over 200K in the last three years.

JT

Edited March 27, 2010 by JThompson

[GrumpyOne]

On what caliber? Really, there isn't a crimp, just removing the bell/flair at the case mouth. But if you really must measure, take the diameter of your bullet, add twice the thickness of your case wall at the mouth, take your calipers at the case mouth as close to the bullet as you can get, and voila! There you have it.

[KennyW]

What is the correct way to measure crimp?

With a case guage, assuming the brass was properly resized to begin with.

Edited March 29, 2010 by KennyW

[G-ManBart]

With a dial caliper or micrometer. Just measure right at the case mouth, and you're set. Normally you want two times the case wall thickness, plus the diameter of the bullet. So, for 9mm, you're normally looking for something like .378" or so depending on the thickness of the brass. R,

[RePete]

I measure a factory loaded round at the case mouth with calipers and setup my crimp die to that measurement then adjust as necessary. This works with jacketed and plated well but not too bad with lead, which generally needs less crimp.

[DCS44256]

No crimp, just taper enough to remove the bell put on the case mouth to facilitate seating the bullet.