10mm case head seperation?

[jerkface11]

I was loading some 10mm tonight when one of the cases took considerably LESS force to size. The case head had pulled off of the body with no resistance at all. How can this happen in a straight walled pistol case? I will post pictures later when I can find the case head as I have somehow misplaced it.

 

[jerkface11]

 

[R.W.Dale]

That is just bizarre and kinda scary given the application

 

[jerkface11]

This was a federal case and I have not hotrodded it. Purely .40 S&W level stuff.

 

[LiveLife]

This calls for another "root cause analysis" ... put your thinking caps on.

 

[Ex]

I'd forward photos of this brass to Federal and ask for comment. Expecially if you're loading at .40 ranges.

 

[rcmodel]

All Federal will tell you is you shouldn't be reloading it.

Further, they will tell you if it didn't fail on the first factory load firing, there is nothing wrong with the brass.

rc

 

[243winxb]

Looks like it came apart where it becomes unsupported. Or the part of the brass that is outside the chamber. Died of old age, many loading? The 40 s&w is rated at 35,000 psi. The 10 mm at 37,500. Not a lot of difference pressure wise. Take a photo of your brass sitting in the barrel, like this 10mm on the left

 

[R.W.Dale]

Look at the extractor groove.

The case head has came out of the case body. Very very strange

 

[R.W.Dale]

Here's an enlargement.

 

[243winxb]

Could be??

 

[25cschaefer]

That is very strange, the brass has failed at its thickest point, could be that it is too hard and brittle, the structure of the metal appears very crystalline. I certainly would not load any more from that lot. I do not see how you could have caused this unless you were using some cleaning solution that chemically hardened the brass.

 

[ReloaderFred]

I've come to expect that from 10mm brass that has been loaded several times, no matter the brand when shooting my 10mm AR. I've got them in Winchester, Remington, Federal and PMC that have separated. They will also come apart about half way up the side of the case, leaving the upper half in the chamber. When I'm shooting my Olympic Arms 10mm AR, I have to carry a bore brush with me to pull the half case out of the chamber. In this case, it's caused by an overly large diameter chamber, which is probably to enhance feeding.

I don't get the case separation in my Colt Delta Elites, EAA Witnesses, nor my S&W Model 610 revolver, but I do in the AR with it's large diameter chamber. You might measure the diameter of your unsized fired brass and see what it's expanding to. That may give you a clue as to what's causing it.

Hope this helps.

Fred

 

[ATLDave]

Never seen that, and I've loaded many thousands of rounds of 10mm. All the case failures I have experienced have been normal longitudinal cracks well above the case head... and all failures were completely non-remarkable at firing, and only discovered during processing of the brass.

But I will say that I mostly load Starline. I have noticed a tendency of FC brass to split more readily. And PPU loses neck tension after just a couple of loadings. Starline is the way to go for 10mm brass, IMO.

 

[Walkalong]

Sounds like Fred has the answer.

10MM AR. Sounds like fun.

 

[jerkface11]

I did some measuring tonight. The only unsized federal case I have measured .418 just above the extractor groove all the other cases sized or unsized including federal were .423

 

[Potatohead]

case head seperation?

Doubt it. Everyone knows you can't have case head separation without the incipient





Im an idiot :banghead: