Blown Primers on M855 ammo

[Shooter45]

I have been seeing a lot of blown primers on the M855 62gr green tip ammo we've been using at work. We're firing this out of Colt M4's with 14.5" and 10.5" barrels. This ammo is stored in conex boxes overseas all season long. We've determined the batch of ammo all has '06 head stamps and wondering if that is being caused from being stored in these conex boxes through all the seasons. It experiences extreme heat in the storage containers, especially the summers.

The cases that I've seen this happen to are not damaged in any way and the primer pocket looks fine like a regular once fired case. We don't know we've had a blown primer until people start having malfunctions in their M4's. All we find is a small piece of the primer in the chambers/action. It appears that the primer is blowing into small pieces because I havn't seen a whole primer yet.

Has anyone experienced this or know exactly what is causing this? All I can figure out is the hot temperatures the ammo has been exposed to has caused a problem with the primer. Any help would be appreciated.

 

[sinister]

Re: Blown Primers on M855 ammo

Extreme heat has a detrimental effect on small arms ammunition. Nitrocellulose smokeless powder will start to deteriorate after long-term extreme heat exposure and storage. No surprise you're blowing primers.

Modern smokeless powder is manufactured with 1 to 2% diphenylamine as a propellant stabilizer.

Ammunition handlers in Ammunition Supply Points and Ammunition Holding Areas are supposed to store ammo in cool, dry places with free air flow (i.e., in earth-covered, temperature stable igloos, bunkers, or revetments [at least with shade -- like an ammo trailer with tarp]).

Storing ammo in Conexes, ISUs, or other tightly sealed and hot enclosures is asking for bad ammo and kabooms. Storing ammo like it's tentage or nuts-and-bolts is a NO-GO.

 

[CST]

Re: Blown Primers on M855 ammo

what about long term storage of the the components and unloaded ammo like the powder?

 

[sinister]

Re: Blown Primers on M855 ammo

Keep 'em in a cool, dry place.

Once smokeless powder starts to deteriorate you can smell it. It won't be a sweet, clean odor, but more like an acidic/aspirin kind of smell. By that time it's failing and it's best used as lawn fertilizer.