When is crimping a must?


November 10, 2008, 11:56 PM
I have only handloaded for 5 different rifle calibers and I have never crimped any thing that I have loaded. I find that they sit very tight and the accuracy is amazing. So, what is the point to crimping? Is it more important on pistol brass or is it even required? Why do you guys crimp?

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Claude Clay
November 11, 2008, 12:00 AM
it keeps the bullet from seating back in the case.
whether from being chambered, from recoil or handling.
neck tension may seem considerable but it cannot be trusted--especially with a round that is chambered and extracted to be re-chambered again. the spring in a tubular rifle magazine along with the recoil with uncrimped ammo is an invitation for murphy to visit.

The Bushmaster
November 11, 2008, 12:17 AM
Revolver cartridges. Especially magnum and use a firm crimp on them.

Rifles like the Winchester and Marlin tube fed magazines (Lever guns) need crimped.

Semi-auto ammunition, but only enough to remove the bell.

Most rifle cartridges such as .30-06, .270 and other cartridges that normally don't have a cannelure on the bullet do not need a crimp.

.38 Special
November 11, 2008, 12:30 AM
I never crimp rifle rounds, with the exception of the big boomers for dangerous game. In a bolt action rifle in a standard hunting caliber, I can't think of a reason in the world why anyone should.

November 11, 2008, 01:04 AM

I crimp everything but but 22 caliber, which for me is 223 and 22-250. The 223 is in an AR and the 22-250 is in a bolt and I have never had an issue with setback in either one.

November 11, 2008, 05:17 AM
I crimp some and others I dont. I do crimp my .223 (only if bullet has groove/cannelure for crimp) due to the bullet getting knocked back into case once in a while when being chambered. I have also had federal factory 50 grain sp do this also. A slight crimp fixed this issue with my handloads. Some handgun powders according to a couple of my books require "high bullet pull" for proper ignition and therefore require a "heavy" crimp.

.223 rifle is a Bushmaster

November 11, 2008, 08:39 AM
So, what is the point to crimping?

In helps in heavy revolver loads to help powders like H110 burn well, and to keep the bullets from creeping forward out of the case enough from recoil to tie up the cylinder.

In auto pistol calibers it can help insure feeding if there was too healthy a bell on the case, and helps aid neck tension in keeping the bullet from being pushed back in the case raising pressures.

It helps give good start pressures in rifle calibers where you can not use an O.A.L. that allows the bullet to have a very short, or no, jump to the lands, and helps keep bullets from being pushed deeper in the case.

Sufficient neck tension can work for many applications without a crimp, but a good crimp is usefull and even necessary in some applications.

November 11, 2008, 08:43 AM
Do you push on the bullet of your newly loaded cartridges and then measure OAL again to check for set back?

If the bullets can not withstand what you think is a reasonable amount of pressure with out moving, they you might consider either crimping or adjusting the diameter of your expander ball.

I've found that some bullets (Golden West 125 gr. .311" FMJ) will not stay put with neck tension alone in a 7.62 x 39 case.

November 11, 2008, 10:25 AM
also a good idea to crimp reduced rifle loads,gives time to build pressure. jwr

Larry E
November 11, 2008, 06:46 PM
Roll crimp on revolver loads, heavier or lighter depending on how hot the load is, hotter = heavier crimp. Sometimes for my M1 if the cannelure is in the right place for the OAL (most .30 cal bullets are cannelured for the .308 anymore. :( Semi-auto pistol loads are taper crimped enough to remove the mouth expansion plus just a nudge.

November 13, 2008, 09:30 AM
Do mouth sealants help prevent setback?

Are mouth and primer sealants worth looking into for long term storage?

November 13, 2008, 09:38 AM
Sealants are not for preventing setback. They are for keeping out moisture. Military rounds are sealed. They may be subjected to harsh conditions. It's up to you.

The old "tar" like sealer for military rounds would set up and help neck tension, but that was just an unintended side affect.

They are a B**** to dismantle. Breaking that seal by seating the bullet a bit farther helps a lot.

Any bullet stored long term can develop a "cold weld" and neck tension will be greater than when first put together. Match shooters found this out when they stored match ammo with purposely light neck tension for a while and then shot it in a match.

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