Military Crimp question

[myhandle87]

Can someone post a good picture of a military crimp? I've got some Austrian .308 that I'm not sure if it has a crimp. It has three little indentations around the primer pocket, is this the crimp?

 

[alanjtc73n]

Yup. Use a swager to get rid of it. Some primer pocket cleaners can get rid of it also.

Sorry, no pics here but someone else might have some. Another military crimp goes around the whole primer pocket while others just use a lacquer.

 

[rcmodel]

Yes.

That is called a "Stab crimp".

A more common type with U.S. ammo is a "ring crimp" that is a depression all the way around the primer pocket.

Make sure your cases do not have Berdan primers. (two off-center flash holes)
You tend to see stab crimps employed with them quite often.

If they are Boxer primed (one central flash hole) you will need to remove the stab crimp before re-priming them.

rcmodel

 

[rcmodel]

You simply must have the Lyman #49 manual.

There is nothing else even close to having the wide variety of bullet weights, types, & styles for every caliber.

That includes lead bullet data not available anywhere else.

The 2009 Hodgdon "magazine" manual available on news-stands for $8.99 is also very worthwhile.

rcmodel

 

[jmorris]

Ring crimp after and before.

 

[kcbrown]

What's the purpose of the crimp? Obviously (as in the case of the previous message's image) the primer can be removed despite the crimp so it's not like the crimp is doing a terribly good job of holding the primer in place. :-D

Also, how much trouble is it to remove the primers from military brass, given the crimp that is (supposedly) in the way?

 

[dispatch55126]

What's the purpose of the crimp? Obviously (as in the case of the previous message's image) the primer can be removed despite the crimp so it's not like the crimp is doing a terribly good job of holding the primer in place. :-D

Also, how much trouble is it to remove the primers from military brass, given the crimp that is (supposedly) in the way?

Its purpose is to retain the primer during the heavy recoil of automatic fire. Mil spec ammo is over designed because it has to by near 100% reliable at all times in all conditions.

Depriming isn't that much more difficult. You'll feel a difference between depriming crimped and non-crimoed cases, buts its not a big difference.

 

[Shoney]

To add a little to dispatch55126's answer:

Sometimes, full auto military arms stretch in the bolt/chamber area due to the heat of extended firing. Wear can also be a factor. Under battle conditions this is a definite possibility. The headspace can increase to the point that a primer could pop out of it's pocket in uncrimped ammo. A loose primer could foul up the mechanism, and the blockage wouldn't allow the weapon fire.

 

[arizona98tj]

Also, how much trouble is it to remove the primers from military brass, given the crimp that is (supposedly) in the way?

The only time I break a decapping pin is when I'm resizing a batch of milsurp brass for the first time. So yes, the crimp does a fair enough job of keeping the primer in place.

 

[Dacoda]

This is a video on YouTube of a guy using an RCBS Primer Pocket Swaging Die at 6:25. http://www.youtube.com/watch?v=THOL_S7Hngs