crimping-how light or heavy?


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gutterman
April 6, 2013, 10:26 PM
When it comes to crimping-roll crimping that is--when should you use a heavy crimp versus lighter? I've always assumed heavy crimp for heavy bullet and powder charge and lighter for the opposite.

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35 Whelen
April 6, 2013, 10:33 PM
Rifle? Revolver? Semi-auto?

gutterman
April 6, 2013, 10:51 PM
Most of my reloads are revolver. I also load 40SW-9mm and 45ACP.

rcmodel
April 6, 2013, 10:54 PM
Assuming roll crimp is only used with revolvers, and can only be applied with revolver caliber reloading dies?

I'm gonna take a WAG, and guess you are asking about revolver calibers!

Roll crimp is used on revolver calibers for one or two reasons.

1. To keep bullets of any weight from being pulled out of the cases due to hard/heavy recoil.
That could apply to hot loaded 110 grain in an air-weight S&W .38 Spl snubby, or a 500 grain bullet in a S&W .500.

2. To increase bullet pull / case release to promote higher pressure initial powder burn when using slow burning Magnum class powders.


As an after-thought, a fairly heavy roll-crimp is sometimes used with light loads with little recoil to promote easier loading when using speed-loaders in a revolver.

rc

gutterman
April 6, 2013, 10:54 PM
To be more specific on revolver--38/357--41 mag--44 MAG--45LC on occasion 460SW and 454casull.

joneb
April 6, 2013, 11:41 PM
Check the last unfired round in the cylinder for bullet jump.

James2
April 6, 2013, 11:51 PM
RC covers it very well, however I caution you when going for a heavy crimp, be careful as too much can bulge the case below the crimp and actually loosen the bullet and perhaps make them chamber hard. This especially if the brass hits the shoulder of the crimp ring just before stopping, when seating and crimping in one operation. So watch how deep the bullet is going and avoid that bump.

Crimp enough to keep the bullet in place against recoil and that is sufficient. Of course you should load a cylinder full, shoot all but one then look at the one left. It may take a little playing to get what you want.

I like to keep the flaring and crimping to a minimum to avoid working the brass too much.

Jesse Heywood
April 7, 2013, 12:29 AM
In the Reloading Library Of Wisdom is a thread How Much Crimp (http://www.thehighroad.org/showthread.php?t=469815) which should answer your questions.

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