2011 bulged barrel, not sure what happened

misterzr

misterzr

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Shooting my 2011 STI Grandmaster in a match today, 9mm major with 8.4 gr of HS6. Everything was going smooth as this gun never gives me any trouble. On a stage with some close up fast shots the gun jammed, cleared it and took one more shot then jammed so hard we had to hammer it apart with a brass punch to clear it. When I got the gun home found the barrel was bulged just behind the comp so bad it won't go though the slide and the ejector has the end broken off of it. First thing I thought was a squib followed by another round, but the shots leading up to the jam sounded fine and I load on a Dillon 650 which I have never had a squib on. Pretty much impossible to have a hot load as the 8.4 of HS6 almost fills the case, and the brass all looked pretty normal.

Lost for ideas as to what happened
 
Sure sounds like a squib even though you say you never heard a change in sound. The only way to get a bulged barrel is to have something stuck in the barrel followed up by another round. The bulge location is also a clue. That would be about the distance a primer only round would go before it got stuck.

The broken extractor is an indication of a severe over pressure in the barrel. Sorry this happened to you - glad you're safe.
 
HS6 is my go to powder for semi autos. Not sure what bullet you are using but 8.4gr of HS6 is way over the recommended limit for most bullet weights. When close to the max small increases in powder can have large increases in pressure. Loading the case full in 9mm can be pretty dangerous especially if the powder is compressed which I suspect HS6 at 8.4 grains will be. With a 124 grain bullet the max recommended is 6.6 grains which is what I run mine at. The highest load I can find is for a 90gr bullet at 8.2gr of HS6. Having said that I agree the the most common cause of a bulging barrel is a squib load leaving a bullet in the barrel then another round being fired. Nowhere for the gas in front of the bullet to go so the barrel bulges to relieve the pressure. Is there an obstruction in the barrel? If the bulge was right at the end it is possible that the second round pushed the first bullet out. Very unlikely for it to be over pressure if it bulges at the end of the barrel.
 
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grinder08 said:
HS6 is my go to powder for semi autos. Not sure what bullet you are using but 8.4gr of HS6 is way over the recommended limit for most bullet weights. When close to the max small increases in powder can have large increases in pressure. Loading the case full in 9mm can be pretty dangerous especially if the powder is compressed which I suspect HS6 at 8.4 grains will be. With a 124 grain bullet the max recommended is 6.6 grains which is what I run mine at. The highest load I can find is for a 90gr bullet at 8.2gr of HS6. Having said that I agree the the most common cause of a bulging barrel is a squib load leaving a bullet in the barrel then another round being fired. Nowhere for the gas in front of the bullet to go so the barrel bulges to relieve the pressure. Is there an obstruction in the barrel? If the bulge was right at the end it is possible that the second round pushed the first bullet out. Very unlikely for it to be over pressure if it bulges at the end of the barrel.
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Recommended limit? This is 9mm major, grinder, there are no limits until things start blowing up.

Here's some user reports:
http://forums.brianenos.com/topic/255177-getting-an-sti-dvc-open-need-help-with-9mm-major-load/
- 9.0gr HS6
- 8.4gr HS6
- 7.8gr HS6

http://forums.brianenos.com/topic/255170-9mm-load-data-for-common-powders-major-and-minir/
- multiple loads in 7.8 - 8.4gr HS6
- highest I see is 8.7gr HS6

http://forums.brianenos.com/topic/254309-open-major-loads-placebo-or-problems/
- 8.6gr HS6
 
adamg said:
Recommended limit? This is 9mm major, grinder, there are no limits until things start blowing up.

Here's some user reports:
http://forums.brianenos.com/topic/255177-getting-an-sti-dvc-open-need-help-with-9mm-major-load/
- 9.0gr HS6
- 8.4gr HS6
- 7.8gr HS6

http://forums.brianenos.com/topic/255170-9mm-load-data-for-common-powders-major-and-minir/
- multiple loads in 7.8 - 8.4gr HS6
- highest I see is 8.7gr HS6

http://forums.brianenos.com/topic/254309-open-major-loads-placebo-or-problems/
- 8.6gr HS6
Click to expand...

Well there you go.... you got your blow up!
 
8.4 grains of Hs6 is just enough to make major, that is what these guns are built for. This same round fired in a normal gun will make it explode. Read the Brian Enos threads referenced about major loads for more info. On closer inspection of the barrel there is a strange looking ring inside just where the bulge is. I have been in contact with Freedom Ventures about this issue and they are very helpful in trying to work it out with STI
 
So it's ok to OVERLOAD a cartridge if you call it "major". Sounds safe to me. Good luck all you major guys....

Btw, I use 9.0 gr hs6 in a .357 with 158 gr campro. That one is good and spicy.
 
What projectile were you loading?

Extreme pressure created that strange looking ring. You had a squib (or other obstruction?) and the pressure created by the followup round ringed and bulged the barrel before both projectiles exited together.

Tada, mystery solved.
 
Make sure you update us when you know what happened for sure. Were you running FMJ's or JHP's?
 
I had a similar experience with a Norc 9mm shooting factory Remington 124 FMJ. Very old ammo in a green box.

I was shooting rapid fire and a round did not sound right and before I could react, i fired another. Bulged and split the barrel. Was not easy to get the gun open. Had to use a vice.

If you fired a major into a stuck bullet, the barrel must be incredibly string to not have blown apart.
 
misterzr said:
Shooting my 2011 STI Grandmaster in a match today, 9mm major with 8.4 gr of HS6. Everything was going smooth as this gun never gives me any trouble. On a stage with some close up fast shots the gun jammed, cleared it and took one more shot then jammed so hard we had to hammer it apart with a brass punch to clear it. When I got the gun home found the barrel was bulged just behind the comp so bad it won't go though the slide and the ejector has the end broken off of it. First thing I thought was a squib followed by another round, but the shots leading up to the jam sounded fine and I load on a Dillon 650 which I have never had a squib on. Pretty much impossible to have a hot load as the 8.4 of HS6 almost fills the case, and the brass all looked pretty normal.

Lost for ideas as to what happened
Click to expand...

1. That first jam was the squib. The next shot caused the ring. The barrel bulge jammed against the barrel/slide bushing and then locked up gun.

2. In the heat and excitement (translation...adrenalin) of the run, you didn't detect both the softer shot report and softer recoil of the squib. The recoil would've been softer due to the squib, hence the jam. Not your fault since you are only human.

3. Your reaction to the jam was normal. Tap rack bang. Good thing it was not a kaboom.
 
easyrider604 said:
1. That first jam was the squib. The next shot caused the ring. The barrel bulge jammed against the barrel/slide bushing and then locked up gun.

2. In the heat and excitement (translation...adrenalin) of the run, you didn't detect both the softer shot report and softer recoil of the squib. The recoil would've been softer due to the squib, hence the jam. Not your fault since you are only human.

3. Your reaction to the jam was normal. Tap rack bang. Good thing it was not a kaboom.
Click to expand...

Is this some kind of thread summary? lol. We've got all that already...
 
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