Need help from the experts on why this case ruptured please

graydog

graydog

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Hi
When I was at the range a week or so ago a fellow down from me was shooting a 9mm 1911 ( I do not know the make or model except that it was for sure a 1911 gun) He had his gun do this twice to him while he was shooting. He said it has happened to him before but only when he uses his reloads. Other then this happening every so often he says they function perfectly and shoot very well.

He told me it has never happened in any of his other 9mm guns and that it only happens when he shoots his reloads in the 1911. Is he doing something wrong when he is reloading or what.

Any help on this matter would be much appreciated. I told him I would ask on this forum and see if any one has any ideas or knows for sure why it is happening.

Thanks Graydog

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The 1911 barrel often leaves some of the case body unsupported by metal. You can see this with the barrel off the gun, and if you drop a round in the chamber. You will see some of the case exposed. If the load is slightly hot (from the primer, admittedly a not totally reliable sign, those loads look hot), then the case can rupture. Normal pressures should work without a problem, such as from factory loads. Plus, if the cases have been reloaded a few times there might be some weakness in the brass from being sized down, and then expanded on shooting hot loads in an unsupported chamber.
 
I would check your seated depth on your round and see if it is fully supported by the chamber the bullet may need to be seated deeper. Field strip and pull the barrel out and put a seat round (dummy) in the chamber and see if the head is seated all the way into the chamber. Seat the bullet further in untll the case head is fully supported. That would then be your OAL.
 
first thing is tell the guy to stop shooting that gun until the problem is resolved!!!! dude better be wearing glasses.there is a chance that kind of blowout will detonate the rounds in the magazine.to the problem now. I can only see one ejector mark on the base,and one mark from the extractor,perhaps there is more but I can't see them.there appears to be a slight shiny mark just above the rupture which may indicate the case is getting a whack on the feed stroke and then the case lets go under pressure.check the feedramp on this gun and see if the top of the frame,not the barrel,has a bit of a radius polished into it.all of us here could probably make a better call if we could have the gun in hand but make sure that guy stops shooting that thing!!!
 
My guess is too hot of a load. Have a look at how the primer is flattened and the metal around the firing pin mark has "flowed" into the space around the pin.

The failure is at the case head which can occur from hot loads which thins the case wall which then leads to excessive case length trimming (thus the thin walls and failure). A larger chamber makes it worse because because case sizing works the brass more than normal. I've seen rifle brass fail like this before.
 
He said it has happened to him before but only when he uses his reloads.
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Surprise surprise. lol. I hear this all too often. 'it only does this with my reloads' :rolleyes:


The vast majority of semi-auto handguns (and a lot of semi-auto rifles) have some portion of the case 'unsupported'. Although even if they didn't, by nature of them being blowback or delayed-blowback (in the case of pistols), as the slide cycles, more of the case will become unsupported as the slide moves rearward.

Judging from the primer and the fact that he ruptured a case, he is loading too hot, or there is some other reload-related problem (bullet seated too deep?).

As to why it only occurs in his 1911?
-Luck?
-Lighter spring that on his other guns?

Tell him to stop shooting those reloads and investigate what he is doing wrong. If you can post his load data we may be able to give some better insight.
 
which then leads to excessive case length trimming (thus the thin walls and failure). A larger chamber makes it worse because because case sizing works the brass more than normal. I've seen rifle brass fail like this before.
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99% of people do not trim straight-wall pistol brass. Unlikely cause.
 
Al-Sway said:
The 1911 barrel often leaves some of the case body unsupported by metal. You can see this with the barrel off the gun, and if you drop a round in the chamber. You will see some of the case exposed. If the load is slightly hot (from the primer, admittedly a not totally reliable sign, those loads look hot), then the case can rupture. Normal pressures should work without a problem, such as from factory loads. Plus, if the cases have been reloaded a few times there might be some weakness in the brass from being sized down, and then expanded on shooting hot loads in an unsupported chamber.
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This.
 
Thanks for all the info guys. When I run into this fellow again I have printed all the comments received here and I will give them to him.

Thanks Again Graydog
 
There used to be problems with custom altered 1911’s were too much of the feed ramp, and rear of the chamber had been removed to better feed wadcutters.
 
caustic said:
the primer is flowing over the firing pin and looks to have flattened, I'd say over pressure
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1shot said:
That primer tells all.. wow!
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Honestly, that primer tells me nothing. I had primers looking exactly like that on all of my ammo. Ammo that barley made minimum IPSC PF. Culprit....oversize firing pin hole.

I'd be leaning toward the chamber support theory myself, with a dose of heavily used/suspect brass.

(E) :cool:
 
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