View Full Version : What caused my barrels to bulge?

Brian S
June 24, 2002, 10:18
Between us my father and I have 3 Imbel barrels, all three have a bulge under the FH about .75-1" from the muzzle. One is barely noticible, one is moderate, and one is severe. All are useable if cut back though the severly bulged one is going to have to be cut back to 16" beacuse its pitted on the last 4" or so.

I was just wondering what caused this? Its hard to believe that all of them were fired with an obstruction in the same place, possibly the were dropped muzzle first and started to get worse as the rifle was fired? Anyone?

June 24, 2002, 10:22
Hmm. Maybe a shit load of grenade launching? Maybe shooting a BFD with a live round? Weird.


Brian S
June 24, 2002, 10:38
I never thought of the grenade launching, thats a good point Byron.

June 24, 2002, 15:06
Grenade launching won't do that.

Obstructions, most likely.

Grenade launching either uses gas or a bullet trap to launch. pressures sufficient to bulge a barrel would do catastrophic things to launchers, et al.

Dropping won't 'bulge' them this way either. Think: this is a barrel intended to withstand 50,000 psig pressure.

June 24, 2002, 15:17
I haven't noticed any bulges in my Imbel barrels, but I found it interesting that on both of them the outer edge of the muzzle is peened over from the muzzle brake being tightened. The brakes are the short combos that come on all of the Imbels. From a side view, the muzzle is slightly mushroomed. The brakes weren't easy to get off, but they weren't all that difficult, either. I found that interesting, as I haven't seen such an effect on a barrel from Stolls or L1A1 flash hiders. I'm not that concerned about it because I intend to cut off the threads, and there appears to be no internal damage.

Could those bulges inside your barrels be due to some effect of the way the muzzle brakes were installed? Just curious as to whether the bulges and the peening might be causally related.

Brian S
June 24, 2002, 17:06
I have no idea weather the damage was caused by overtight flashiders but I makes sense in that if the hider was screwed down too far it could act like a press, compressing the end of the barrel forming a mushroom bulge in the rifling. I would think however that the barrel threads would strip long before the barrel would distort. This might be an interesting project for someone who had an otherwise unuseable barrel and some free time though..

Seth Livzz
June 24, 2002, 23:10
Did this perhaps cause your barrel to bulge? :D :D :D


June 24, 2002, 23:12
Is that Falicity?

June 24, 2002, 23:13
You probably could have gotten them replaced.
Maybe you still can if you just got them

Brian S
June 24, 2002, 23:24
Two of them were included in grade 3 kits from Dans, the third is a replacement that Dan sent me on credit because one of the original kit barrels was pitted. The replacement barrel is perfect when viewed from the breech end but it is bulged and frosty on the muzzle end. I am still planning on using it since this rifle will be a 16" carbine. I will send both barrels to Gunplumber with the rest of my parts and let him make the final call. Its possible that the slightly pitted barrel has a better throat and therefore more life. Its pits are tiny and you have to look to see them, hell they might even burnish out with some shooting! I'm not going to hassle Dan about this issue any more, he already took care of two nitpicking requests and after all they are grade three kits and nobody claimed they all had perfect bores!

P.S. Dan is a great man to spend money with. Very fair.

June 25, 2002, 00:14
Is that Falicity?

Nope,,I think its kamiyama