Barrel bulge

[Idz]

Had an interesting problem. Was practicing with my Glock 30 45acp and had a failure to extract. I did the normal tap, rack, assess drill and a few rounds later the slide jammed open. I had to hold the slide and whack the muzzle to get it unjammed. Manually cycled a few times and all was ok but the next round it jammed again. Figuring something was broken, I stripped it down and found no problem with the barrel or internals. Upon cleaning the barrel I noticed a slight gray ring about 0.1" in front of the chamber. I got out my micrometers and measured the barrel OD and found it had bulged about 0.004" in that spot, much to small to see or feel. I chucked the barrel into my lathe and took a 0.002" cut and now everything works fine. I have seen bulged barrels but never one with such a slight bulge that seems to have zero effect on performance and is such a mystery as to how it happened.

[Harter66]

I'm no professional but it would seem to me you had a problem that generated an undesirable situation about an inch in front of the chamber and you should be looking for the ejected case from just before the first jamb for an answer . I'd bet part of it is MIA . It probably hung up about where the ring is and left as a brass band on the next bullet .

Under pretty unlikely but not impossible it could be a ring . I'm reaching here but the bullet gets set back in the mag driven way out when it chambers push d a little more by a mag primer then the powder pressure catches up with the slowing or stopped bullet . Pop bad stuff happens .
If it was me which it isn't and my gun which it isn't I'd take the barrel out and not shoot it anymore until it was magnafluxed at a minimum or replaced . It's cheap reassurance and cheaper confirmation if the line is a pending failure .......it might run 10,000 rounds , you might be lucky to have a gun in one piece .

If it swells out it can rupture , removing the swelling just hides the cause .

[cwtebay]

Where did you take the 0.002" cut?
What were you shooting when that occurred? - new load / bullet / brass....? How many rounds have been through the pistol? How many rounds have YOU put through it? Is this a new load?

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[Cap'n Morgan]

Any chance you had a primer-only load and ended up with a boolit in front of the next round?

[Tar Heel]

Since we are not at war and your gun is not in a combat environment necessitating continued use, I would suggest replacing that barrel.

[NyFirefighter357]

Spend the $140 now on a new barrel or you may pay a much higher price later.

[country gent]

While turning the "bump" off seems to have fixed the problem, there is now a thin spot in the barrel close to where pressures are highest. This area is also under more internal stress do to the bulge. I may run forever it may slowly expand more or it could fail. the scary part is you have no idea when or if. .002 dosnt sound like alot but coupled with the added stresses and original overload ( if it wasnt an over load then the barrel was weak there from new) it is nw very questionable

[Idz]

I was shooting a relatively mild 45acp reload of 230 gr cast (~9-10 BHN) truncated cone with powder coat and about 4.9 gr of win 231. I picked up all the brass and none of the cases showed even slightly flattened primers indicating high pressure. The puzzling part is if the fail to extract was a squib why did a couple more rounds fire before the jam. The bad barrel measured 0.628" diameter at the muzzle and 0.634 at the chamber end. A good barrel measured 0.629 at muzzle and 0.631 at the chamber. I turned down the bulged barrel so it was 0.630 max diameter. The jam was caused by the barrel wedging in the slide muzzle end 'bushing' hole due to being tilted off the slide axis when unlocked. Its odd they build such a tight tolerance for an unlocked barrel.

[1006]

I think that you had a light loaded bullet stick in your barrel-just in front of the chamber. You cleared the brass that failed to extract as a result of the light load, and then chambered another round. The next round fired, but also pushed the jammed bullet out of the barrel and causing the bulge.

Glock might help you out with a new barrel.

I once got very lucky and had a bullet come to a stop half way out of the muzzle. It was a 357 revolver. The sound alerted me that something was wrong. If the range had been full of shooters, I am not sure that I would have noticed while doing speed drills.

[Cap'n Morgan]

If it indeed was a "sandwich" (with a boolit already lodged in the barrel) the case will not show any excess pressure as the pressure spike happens between the two boolits and not in the chamber area.

[DougGuy]

Well, if you can find enough metal to turn off the outside, it had to come from somewhere! Push a tightly patched jag down the bore, I will bet it gets loose when you get to the part you turned down, and there's the bulge, on the inside.

I would NOT use that barrel.

Glock barrels are harder than woodpecker lips. I have to use carbide to throat them. They are EXTREMELY strong barrels so you had to have a significantly over pressure event occur. Now the barrel may cycle again but you are at an unknown place with it's metallurgical properties and there is no way to safely speculate whether it would be safe to fire or unsafe.

The absolute best place for that barrel would be somewhere in the brown truck, on the way back to Glock.

[Misery-Whip]

If it were me I'd be looking at lone wolf.

It's been stretched, next time it won't take as much to do it again.... whose hand will it be in?

[wv109323]

On the first failure to eject, was there normal recoil? A squib in a 1911 will not function the slide unless an extremely light recoil spring is in use. Also a squib produced no recoil.

[Combatmedic63]

Just me, but I would never turn material off of a barrel. You are thinning a necessary portion of what is supposed to be there. Spend the money for a new barrel and as stated above, try to find the culprit case and figure out why this might have happened and if it caused an undiscovered damage to the internals.

[Rapier]

I have put a bunch of match barrels in my custom Glock builds, the factory barrels shot as good as the “match” barrels, from a rest. So I would just get a new M-30 barrel and roll on. No, Glock + cast bullet complaint to Glock.

[GregLaROCHE]

Get a new barrel. Otherwise, every time you pull the trigger, you’re taking a chance. You are lucky new barrels are available at reasonable prices. It would different if it were an antique gun.

[country gent]

If memory serves me 4.9 grns of 231 with a 200 gn bullet is getting close to upper end and a 230 gn would push it up some more.

[cwtebay]

If memory serves me 4.9 grns of 231 with a 200 gn bullet is getting close to upper end and a 230 gn would push it up some more.

Great observation - it looks like 4.9gr of 231 is 14% over the maximum recommended load for a 200gr bullet in any of my resources.

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[kenton]

Hogdgon has 4.3gr of 231 as a starting load and 5.3 as max for a 230gr LRN at a COL of 1.200in

https://shop.hodgdon.com/reloading-data-center

I do agree with replacing the barrel. Also possibably smashing it with a hammer or vise before discarding it to keep a cheapskate like me from finding it and trying to use it.

[cwtebay]

Hogdgon has 4.3gr of 231 as a starting load and 5.3 as max for a 230gr LRN at a COL of 1.200in

https://shop.hodgdon.com/reloading-data-center

I do agree with replacing the barrel. Also possibably smashing it with a hammer or vise before discarding it to keep a cheapskate like me from finding it and trying to use it.

You are correct - thank you for sharing that!

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