Case head separation from early extraction in a gas gun

[jlow]

I heard recently that due to “not enough dwell time before the action unlicks and begin extraction” it is possible to cause a case head separation which is news to me.

I’ve heard of rims being ripped off when this happened, but… However, I am open to this idea but just find it hard to believe that extraction is strong enough to cause a case head separation. Would be interested in hearing from people who have experienced this.

FWIW, my understanding is this can happen in a Garand and/or an M-14. Or at least this is the claim.

 

[Shynloco]

Hello my friend,
Boy that's a new one on me. Having rarely experienced head separation of a casing, I've have been under the understanding that it takes a "detonation" at least to create enough energy to rip apart a casing. So I'm all ears and willing to consider any REASONABLE explanation of the process and thereby learn something new today.

Alex

 

[NorCalMikie]

Sounds like a pretty good line of BS to me. I know that my M1A will destroy a rim if the case is stuck in the chamber before it pulls the head off.
Case head separation? Brass was overworked, probably more than once. Been there, done that.

 

[Geno C]

The brass will look like a belted mag case befor it'll separate the head from early extraction. At least in a AR platform. I can't see how the bolt would pull the head off that would mean excessive headspace to me.

 

[jlow]

You guys are basically echoing my own thoughts. I've always thought the really only reason for case head separation is due to over bumping the shoulders but well I wanted to keep an open mind...

 

[ireload2]

Use a little imagination man.
Suppose Billy Bob has a bad case that is about to separate. He loads it and fires it with a slow burning powder in a gas gun. When it is fired in the gas gun the port pressure is high while the case is still expanded and stuck to the chamber. The gas pressure blows the bolt back and the case head comes off. Billy Bob thinks he has a wicked extractor when it was mostly a bad case caused by excessive FL resizing.
Morons can fire cases that have been sized excessively and make the heads come off in a bolt gun so pulling such a case apart in a gas gun is no big deal. The guy that it happens may not understand how it happened. It has to be something defective other than his skill level.

I heard recently that due to “not enough dwell time before the action unlicks and begin extraction” it is possible to cause a case head separation which is news to me.

I’ve heard of rims being ripped off when this happened, but… However, I am open to this idea but just find it hard to believe that extraction is strong enough to cause a case head separation. Would be interested in hearing from people who have experienced this.

FWIW, my understanding is this can happen in a Garand and/or an M-14. Or at least this is the claim.

 

[M-61]

The brass will look like a belted mag case befor it'll separate the head from early extraction. At least in a AR platform. I can't see how the bolt would pull the head off that would mean excessive headspace to me.

Exactly. I have a perfect belted 5.56.

 

[jlow]

Use a little imagination man.
Suppose Billy Bob has a bad case that is about to separate. He loads it and fires it with a slow burning powder in a gas gun. When it is fired in the gas gun the port pressure is high while the case is still expanded and stuck to the chamber. The gas pressure blows the bolt back and the case head comes off. Billy Bob thinks he has a wicked extractor when it was mostly a bad case caused by excessive FL resizing.
Morons can fire cases that have been sized excessively and make the heads come off in a bolt gun so pulling such a case apart in a gas gun is no big deal. The guy that it happens may not understand how it happened. It has to be something defective other than his skill level.

Dude, if you actually read my post, you would understand that I am very skeptical for the obvious reason I stated. Just keeping an open mind...

 

[Bart B.]

M1 and M14 bullets are normally several feet down range when their bolts twist to unlock. Barrel pressure is quite low.

 

[243winxb]

http://www.hornady.com/ammunition/superformance-in-gas-operated-firearms

the gun is still in the process or firing while it’s trying to extract the cartridge case.

I would guess, it doesn't have to be this powder? Wrong adjustment on the gas or the gas port size/location is not correct?? (AR15)

 

[Rsadams]

Exactly. I have a perfect belted 5.56.

Have you tryed a heavier buffer?? H1 or h2 ? Or even that with a sprinco blue spring... I use their white spring and the h buffer.. Now colt has gone to the h1 in their carbine length gas system..

 

[XTR]

The only examples of case head seperation I've ever encounted in my rifles or others the cause has been due to excessive oversizing resuling in the shoulder being pushed back too far, or the same effect from firing brass sized for one chamber in another that is longer.

I could believe ripping the rims off, but not case heads coming off.

 

[Milo 2.0]

Next time you hear this theory, I'd tell them to back off the powder.

 

[DirtySteve]

I have seen this happen to old cases that were ready to be tossed out as trash. In decent brass I have only seen some tears in the runs from being ripped out under pressure(high chamber pressure). The best thing that can be done for a has gun is to add an adjustable gas block. Accuracy improves and less case damage.