I have a Browning Citori, 12 ga, 26" barrels. Bottom is choked improved modified[u][/u]from factory and top has been reamed from full to modified with an extended steel choke. I bought this gun in 1995 and have used it as my waterfowl gun for the past 27 years. It only shoots 3" steel in either BB or #2. I've used Federal and Winchester shells primarily but fed it a diet of Kent a year a go and this year the Challenger brand made in Quebec, CA. Late this season I noticed a bulge in the bottom barrel right at the choke but on only one side. It could not have happened earlier in the season because I clean the gun after every outing and would have noticed. It did not bulge in an entire circumference as I have seen other barrels do. I am perplexed about the cause. Could it have been the new shells, but I had already put a flat of those shells through it before the bulge? We were hunting in snow in lay down blinds and I'm wondering if I inadvertently stuffed it with snow, but wouldn't the pressure have blown out the snow because even though it may have been stuffed with snow at the end it would not have been packed in hard? Or perhaps after 27 years the metal fatigued? Maybe something I've yet to consider? And then why only bulge on one side and not completely around the barrel? I don't think I could take good pics to properly show the bulge and have not done so.

I have taken it out on 2 occasions since put 100 rounds though it and the bulge seems static. I'm still hitting the target even at good distance but have yet the chance to pattern it and see if there has been a change.

The strangest thing I find about your post is the fact that 1995 was 27 years ago. My, how time flies.

Fleeting perhaps but hardly strange.

Can't answer your question as to why but I have a vintage over/under that has the bottom barrel exactly the same as you describe, being there is a slight bulge on one side only about where the choke is. It was like that when I got it so just guessed that someone was maybe shooting steel shot through it.

Time flies. That is absolute truth.

Sadly, I can offer no absolute truth in the question of your duck gun. You are correct maybe, 9,999 times out of 10,000, the snow will get blown out of the end of the barrel. What happens the time it doesn’t, is usually destructive. Because it happened in front of the choke, and is not perfect in circumference, I’d lean toward something being in the tube, near the end, at the shot. It could have been debris from a previous shot, coupled with snow, but, it would appear it created a localized pressure spike that was able to deform the metal where the pressure developed by the shot is actually lowest, the end of the barrel.

I would hate looking at it, and the fact it happened. But, from all reports I have looked at, bulges at the business end are pretty much a cosmetic nuisance. The magic words here, might be “duck gun”. They are in perfect condition the first time out, after that, well, often, not so much.

I’d keep an eye on it. Measure it after each use with a micrometer, and commit the number to memory. It it gets worse, get a different gun. But, I would keep using it, until that happened.

Good luck.

Best,
Ted

If the top was FULL choke originally, are you saying the bottom was IMPROVED MODIFIED rather than improved cylinder? If that is the case, it is my understanding that steel shot, of the sizes you mention, should not be shot through chokes tighter than modified which improved modified would be.

As to the cause of the bulge, it would be my guess that at least one shell had an occurrence of "bridging", where the shot sort of sticks together in a clump resisting the chokes compression of the shot column and resulting in the bulge. If your bottom barrel is improved CYLINDER it still might have been bridging but could also be something else.

I vote for shot bridging as well.

Sadly, I’m kind of glad this thread popped up.
Because they are modern barrels.


Steel shot when pushed through chokes represents an incompressible obstruction to the choke occasionally.
You never know when it will occur.
If the barrels are not elastic enough,In that moment you get a bulge.

I wish it weren’t true.

It may not occur for decades. But that one time,…..😔

From all of the details provided, my opinion is that a bulge due to shot bridging would be unlikely in an improved cylinder choke. Problems due to steel shot bridging seem to occur mostly in tighter choke constrictions. And I agree that a bit of light fluffy snow would most likely get blown out ahead of the shot charge. But snow is a relative term. ranging from light powder to almost slush. When you said the bottom barrel is choked "improved", I am assuming here that you meant improved cylinder.

But if you got some snow in a warm barrel right after you had fired a previous shot, it could have melted, and then froze, leaving a depost of ice at the bottom of the tube. Ice will not get blown out, and the wad and shot charge would have to displace it, and the barrel wall, to exit. That might also explain why the bulge is at the bottom of the tube instead of being more circumferal.

Bulges are much more difficult to repair than dents, but if it is small and not too close to a rib, a good gunsmith might be able to iron it down to make it less obtrusive.

Sorry to all but the bottom barrel is choked modified. My mistake.

I haven't owned a lot of Citoris, but I did use several when I shot Sporting (still own my last one). I bought the first ones over a few years, but they were all well before 1995. I didn't pay a lot of attention to the hunting guns, but the target guns were all made with choke tubes. My very first I bought was my favorite, had the standard size tubes, and even it had tubes. I thought they had switched to tubes well before that.

Although I purchased the gun in 1995 it was second hand and mfg well before that. I have not checked the serial number to determine when.