Primer malfunction question

[dynamike]

Quick question on a primer that damaged the extractor on a friend's rifle (22-250 Savage). The round had some green corrision around the primer b4 he shot it, after it blew the primer cup out of the case (leaving the side still in the case), and damaged the extractor. We were wondering is what was the green corrision? Bad primer? Powder?

 

[dynamike]

Quick question on a primer that damaged the extractor on a friend's rifle (22-250 Savage). The round had some green corrision around the primer b4 he shot it, after it blew the primer cup out of the case (leaving the side still in the case), and damaged the extractor. We were wondering is what was the green corrision? Bad primer? Powder?

 

[john traveler]

Green corrosion is characteristic of copper salt residue. The corrosion very likely partially ate through the primer cup, causing it to blow out on combustion of the powder. The question is, was the corrosion internal or external to the cartridge. I would think it much more likely that the corrosion was external, since internal decomposition of the powder would likely deactivate the primer too.

In examining corroded cartridges, water, mouse urine, or some such contamination is always involved in the action. Where were the cartridges stored?

 

[dynamike]

Thanks john...ammo was stored on the gun in an outside, nonheated shed

 

[dynamike]

the offending primer

 

[john traveler]

Uh huh. Complete circumferential separation of the primer cup. That is positive evidence of either defective primer cup manufacture, or more likely, the external corrosion that ate away the primer cup, thinning it to the point of rupturing on firing.

I've seen US M1 .30 caliber Carbine and .30-06 military brass that had been chemically washed and left neglected and forgotten. Years later, upon attempting to decap the cases, a large percentage of the primer cups separated just like that, ruining the case for reloading.

In your example, I would think that the external corrosion on the cartridges was enough to show exposure to something corrosive (mouse piss?) and long term exposure to your high humidity did the damage.

 

[dynamike]

Thanks John. It was just baffling both of us. The rifle was undamaged...just shot a detent ball out from under the extractor.

 

[Dale53]

When I hung out at Camp Perry, range pick up brass was often subject to alternating wet and extremely hot. Military primers were corrosive. The combination OFTEN left the primer walls in the case when we tried to decap them. Difficult to remove them. We were all a bit "money shy" in those days and went to great lengths to recycle most anything. The cases were not damaged but the combination of dampness, heat, and corrosive primers were sure hard on the fired primers. Yeah, "the good ol' days", NOT

.

It sure did teach us to appreciate what we have, tho'.

Dale53