Sidearms & Scatterguns Glock Barrel Bulged after Hot Load

[Gustav7]

Buddies Glock 19 barrel had a nice little bulge in it about an inch in front of the end of the chamber. I thought at first he maybe had a squib, followed by a round that pushed it out but bulged the barrel, but he says he felt a light round(reload), so he took his barrel out and checked to make sure it wasn't a squib. The following round was a definite hot round, and he said his slide stuck back.

He finally got it apart and noticed the bulge in the barrel. I've shot thousands of these reloads out of my glocks, sigs, and springfields without issue so I know the load is good. However, we had a reloading day a while back where it was super humid in my shop and we kept getting sticking powder in my powder measure. I felt like I measured and corrected any bad ones, but he helps me reload and doesn't quite have the experienced eyes that I do when it comes to looking in 9mm cases after the powder drop. So my thought is he had a light powder drop, followed by a heavy and didn't notice. We only reloaded about 200-300 rounds as I called it quits due to the humidity issue.

My question is... why did it bulge so far forward? It would seem the pressure would have gone down a bit by then? Is that the weakest part of the barrel? Did he maybe have a bad barrel? I highly doubt it was a full double charge, but maybe 1.5 charge.

Load is 124gr Hi-tek coated TC's. 3.7gr Titegroup.

In the pics, you can see the dark ring where the bulge is.

 

[BCP]

Double charged I bet.

 

[Gustav7]

Double charged I bet.

I would be really surprised if it was double charged. The way we reload and the way I taught him, its more likely that it had some powder stuck in there, and possibly got a heavy charge. I also would assume that 7.4gr of titegroup would blow the shit out of a barrel, not just bulge the barrel an inch down the barrel, but I could be wrong there?

Most likely a bullet got stuck in the bore, the following round pushed it out. I have a makarov that happened to and it looks identical to your pic.
Seen it with others.
The one overcharged accident blew a friends xd clean out the top of the chamber.
Glad he didn’t get hurt!

This is what I was thinking, but wasn't sure as he says he for sure looked down the barrel, but memories are sometimes hazier than you think.

 

[MK20]

It is impossible to get a bulge like that without a bore obstruction. A hot round will not bulge the barrel until it destroys the action

 

[kentuckyMarksman]

I'm thinking it was a squib, then the next round pushed it out.

I doubt it was a double charge. I think there would be more damage to the chamber area.

 

[Old Man with Gun]

If the customer is expecting you to repair/replace the damaged pistol I would weight the accuracy of the story with the motive.

I have not seen many bulged barrels, but every one was a squib.

I also remember being warned not to shoot lead from a glock, as leading can build up. Don't know if leading could have increased back pressure.

 

[Gustav7]

It is impossible to get a bulge like that without a bore obstruction. A hot round will not bulge the barrel until it destroys the action

I'm thinking it was a squib, then the next round pushed it out.
I doubt it was a double charge. I think there would be more damage to the chamber area.

This is what I was thinking but don't have a lot experience in diagnosing these issues, so I appreciate the input and confirmation. I didn't want to eat my own words when I talked to him, but I was thinking the same thing.

Ya the chamber looks great, and there's no discernable difference between his chamber area and one of my Glocks with only a few hundred rounds down the tube. Also, no damage to the slide, buffer spring, housing/frame, etc. The only reason the slide stuck was because of the bulge.

If the customer is expecting you to repair/replace the damaged pistol I would weight the accuracy of the story with the motive.
I have not seen many bulged barrels, but every one was a squib.
I also remember being warned not to shoot lead from a glock, as leading can build up. Don't know if leading could have increased back pressure.

This is a good friend, so he's just simply trying to figure out what happened. Shooting lead out of a Glock is fine as long as you don't have undersized bullets, but I've also never had an issues with coated lead. These are Hi-Tek2 coated lead, which has not given me any issue in thousands of rounds, and I know people with hundreds of thousands of rounds without issue on the coated stuff. His barrel is also clean other than that, no obvious leading.