Military Crimped Primer??

[DoubleA]

Hello all,
What is a military crimped primer, and how difficult to reload?
Thanks,

[Castaway]

For some reason, unknown to us mortals, the militay decided years ago to crimp the primer into the case.  Not a big deal when you punch and size, but a real buger when you try to reprime.  RCBS makes a tool that fits in your press that swages the primer pocket to allow you to prime without difficulty.  Trying to seat a primer without changing the existing primer pocket could result in a detonation.  You can also use the pointy end of a chamfering tool to remove the crimp.

[Donna]

Hello DoubleA,

Because of the various and adverse environment that the military ammunition is required to function flawlessly in, the military required its primers to be sealed with a primer sealant and crimped likewise the bullet is also sealed and crimped. The bullet and primer sealant are different from each other. The bullet sealant is like a tar while the primer sealant is lacquer, the topcoat of nail polish also called “Hard as Nails” is a very good primer sealant, and is used for waterproofing. The primer crimp is used to make sure the primer does not back out during handling and/or the operation of the firearm it is used in. In modern small arms, like the M16, which are subject to what is called “Slam Fire” the military also requires a slightly thicker primer cup. Even though the primer cup still shows the signs of the slamming of the firing pin they are strong enough not to detonate or cause a “Slam Fire.”

Like Castaway mentioned, RCBS makes a tool that works on your reloading press that swages the crimp out of the primer pocket or that is what it is suppose to do. I have used this tool for many years and sometimes it worked and sometimes it did not. Some cases required several times being swaged and some cases are just to be tossed. There is also a tool that cut’s out the crimp but I have never used that tool. Nowadays, I would not mess with cases that have crimped primer pockets, I buy new brass for all my work and play.

Donna :wink:

[Thomas Krupinski]

I have used the RCBS primer pocket swager and for the most part it works.  Difficult to tell before the next reload if the primer pocket has already had the crimp removed with that tool.

Now I pretty much just cut out the crimp by putting a little bevel on the edge of the primer pocket lip with one of the neck deburning tool.  Those cases are easy to tell that the crimp has been removed and work very well.  Used it from 30/06 down to 5.56.  Only have to do it once.

[New Hampshire]

Ditto everyone else and to add:  Remember Military brass is usually thicker, thus reducing case capacity.  You will need to adjust your charge weight down.  If not you can get some high pressure and bad things will result.
Brian M.

[John Traveler]

The main reason for crimped-in primers on military ammunition is to prevent primer's backing out in automatic and semi-auto guns.  Such an event would likely cause a gun jam.  Except for the ammunition made for the Pederson semi-auto rifle (primer actuated) all military rifle and most pistol ammunition has been crimped since machine guns and automatic rifles joined the world's armies.