Is it possible to repair a minor barrel bulge in either a steel barreled or damascus barreled double rifle? Would the barrels have to be separated in order to do it? Would a minor barrel bulge make a barrel unsafe? Is there anyone in the U.S. who can do this repair?

If there is enough steel in the barrel, and the bulge is small, I have seen a gun rebored, slightly larger, and the outside of the barrel dressed to remove the bulge.

I have an aquaintance that regularly shoots a .450ish British hammer gun with a slight bulge in the right barrel. Idunno how he determined if it was safe or not,but shoot it he does...Bulge is slight, you can feel it with your fingers....

This is question that has two answers . Yes and no . To be frank with out an experienced rifle barrel maker examining it any comments are little more than nothing . There are far more variables to consider ,than if it were a shotgun .I do not know who would be the man to consult but it will be very easy to do further damage if the work is not done correctly ,if it can be done at all .

A bulge is different from a dent in the metal is stretched outward not compressed inward. From a cosmetic viewpoint a bulge can often be returned to original "cosmetic" position but safety is another question. You have to ask why it bulged in the first time in that place and will the same reason occur again causing another bulge or worse to occur. Metal that has become elastic tends to be elastic again and again.

If you had a bulge in your aorta and a doctor told you that he could push it back in place, trim any extra off the surface would you do it? No I hope not. Same thing with a bulged barrel. Remember Tony had a bulge barrel repaired, reproofed and had it crack, fail again, in less than ten rounds.

Would it not be different with a rifle barrel? It seems that it would be thicker to start with?

It's much thicker but the pressures are much greater as well. I'd call JJ at Champlin and ask him what he thinks. I would not fire it myself until it had been pretty much certified safe by someone I trusted to know such things through experience. "Let fortune yield to experience"......the motto of one of my alma maters.

Yes I agree Last Dollar it, a rifle barrel, should be thicker to start with but it failed or bulged once. Ever blow up a balloon? Notice how hard it is to blow up when new. But after it is stretched, by blowing up once, it is easier to do the second time. Once metal is elastic it will be elastic easier the second time. The owner does not state where the bulge is on the barrel. If it is near the muzzle perhaps the barrel can be shortened. If it is at or near the chamber I would be very worried about shooting even a repaired barrel.

I know this guy, Bob knows him too, who has a very neatly repaired left hand. Skin and bone grafts are wonderful things when performed by a very capable surgeon. His injury was from a modern gun from a very good maker who just happened to accidentally bore the barrels a tiny bit eccentric. It was fine right up until it blew up. Food for thought.

Looks great and works kinda OK. But definitely not OEM.

LD1,
I would recommend you discuss your issue with Butch Searcy. He manufactures double rifles and can likely guide you on what to do.

KY Jon,
I respectfully disagree with your analogies. Steel behaves nothing like any of the materials you compared. A bulge as described will undoubtedly result in a measurably stronger local area, believe it or not.

Would a possible solution be to sleeve the barrels to a smaller caliber?

Chuck is of course correct on the strength of the steel actually increasing in the bulge. A bulge in a rifle bbl most likely came from it being fired with an obstruction in it. I heard of one instance where someone noticed a slight bulg in their rifle bbl & investigation revealed that apparently at some point a bullet had shed its jacket in the bore. Succesive shots had passed through the jacket & ironed it into the bore producing the bulge on the outer surface. He just left it alone & kept using it. I have also heard of several other cases where folks continued to use a rifle with a slight bulge in them. In the case of a dbl rifle it would seem a certainty the ribs would have to be removed & would still be quite difficult to do a total fix, as would be hard to get in the area adjacent to the other bbl. If the bulge is slight enough that the bulllet bridges it in its travel through it would most likely be best to simply leave it alone. As to dressing of the exterior for cosmetic purposes wall thickness would need to be determined to see if this were advisable.

A naive question - if the rifling has gone bad in the area of the bulge, can it be restored? Is it possible, or necessary, to re-rifle a short segment?

Given enough effort and money, about anything can be done. All of these questions about what to do with a problem on a gun are almost without variation, anchored by a limitation on how much to spend to fix the problem. Obviously, the barrels were made separately and assembled, so disassembly and barrel replacement is possible.

For this one, I'd see if the gun shoots acceptably first. If so, a cosmetic solution would be the most I'd do, if I did anything at all.

If the gun does not shoot acceptably, due to this bulge, I would start looking at more difficult solutions. If the bulge is within a couple inches of the muzzle, I might consider simply counterboring the rifling back past the bulge.

I know it's been tossed around before, but is the bulge actually stronger or just have some unknown stress introduced. Is there a practical way for someone to determine if it's safe to shoot, just to decide if it's accurate enough to leave as is.

Yes, you can use real data.

If you look at 4140 in the table below, you can see that normalized 4140 has a 46.8% reduction in area in the 6th column. That was the cross section reduction measured on a failed coupon (a statistical sample, no doubt). The mild steels have even more reduction.

You can measure your barrel wall thickness at the bulge and the adjacent undamaged area and calculate the reduction at the bulge. If you're not anywhere near this reduction in cross section and you inspect for cracks, remaining strength is not your concern for determining if it's safe to shoot. Other factors may be reason for deciding it's not safe.

As with using any engineering data, use conservative judgement in applying the data. But, you can see that the large amount of reduction in the cross section is common to most of the steels. So, a small bulge like mentioned by the original post, is not going to have a reduction of area (wall thickness) that comes anywhere near these published reductions.

There's more calculations you can do to get a more accurate estimate of the remaining strength vs. the original strength, but if you don't have much reduction, it's really not necessary

I would think it possible to bore out the barrel and fit a liner of the same caliber. Of course this assumes that the original barrel is of sufficient diameter to be relined and that the cartridge it is chambered for is of low enough pressure to use a liner safely.

What caliber are we talking about? A 9.3x72R is 'way different than an 8x68RS or a .375 Flanged Magnum.... And the external bulge might still be cosmetically unpleasing. And the rifle would still require re-regulation, not a cheap or simple process.

OK, LD1, you have been playing with us.
Please specify
what double rifle.
what caliber.
Where the bulge is located.
Twist or steel.
Hammer or not
Any other issues with the gun.
Etc, etc,
Pictures would be helpful
Mike

I am not "playing with anyone" This is not a game. I am seriously considering purchasing an Alex Henry double rifle in .360 BPE calibre. I am waiting for more information from the owner. He has only said that it has a "slight" bulge in one of the bores. I was very specific in my last E-mail to him concerning the bulge. I have not gotten a response from him yet. When I do I will post it. I agree with the gentleman who stated that the bulged area would exhibit a higher hardness value, but I am most concerned about the effect of non-metallic inclusions that are certainly present in 100 year old steel. A stringer of inclusions could have caused the eventual split in Tony's shotgun barrel that occured after passing proof. I would like to have someone with experience in metallographic cross sections of barrels from the 1800s to give his opinion on the effect of inclusion material in steel / damascus barrels.

Ld
Thanks for revealing that you indeed have more than a little understanding of metallurgy. I think you'll figure this out. There was an effort here to get real data on vintage barrel steels, but it somehow evaporated when our resource for the tensile testing and other lab testing suddenly vanished. I had made a tensile fixture for 12g shotgun barrel coupons and sent it to him along with some example barrel material. Others sent samples as well..

Thanks
The Alex Henry was most often seen with the 2 7/16 inch case.
Is this one that case or the more common 2 1/2 inch case?
There were nitro loadings for the BPE, but I suppose you will be
staying with the black powder loads?
Will you be using paper patched, or cast bullets?
Velocity is from 1025 fps to 1700 for most known loads.
With the bullet diameter around .366 any good 9.3mm bullet should work.
The longer heavier bullet might be able to span the bulge and maintain accuracy
Good luck
Sure hope the bulge is on the muzzle end
Mike

Mike,

I have a couple of original .360 moulds and I hope to use one of them. I do not know the case length of the rifle yet. I am hoping to get more information from the owner. I E-mailed him over a week ago now and have not had a reply.

Chuck,

I spent 32 years analyzing steel at a major steel
company's research center. A gentleman from British Steel gave me a nail that came from a Roman fort in England. Analysis of it showed that about 50% of it was inclusion material. Scary!
In the 1970s inclusions were found in the majority of metallographic cross section fields. Now, the 4140 steel that you referenced would typically show very very few inclusions. We have come along way with steel cleanliness, but I have no experience with inclusion content in the 1800s. It would be a very interesting study.

LD,
I recall being invloved in a few "inclusion investigations" over the years in aerospace. One that sticks out is tungsten inclusions in titanium lockbolts. It was coming from TIG welds done by low skill Russian shipyard welders that built Russian titanium subs and were later salvaged and the scrap sent to the U.S.. Each time the welder stopped the welder and incorrectly "dipped" the tungsten tip in the puddle as it solidified, they had to break off a small piece of tungsten. The vac-arc-remelt process and ingot trimming wasn't getting rid of it.

I think steels of the turn of the century and earlier will be very dirty on average. But there may be some really clean stuff in these specialized applications like guns.

Chuck,

You may well be right concerning expensive rifle barrels. One of the theories about the Titanic disaster is that cheap rivets were substituted for more expensive ones in the hull. These rivets failed when struck by the iceberg. Metallographic cross section of some rivets saved with a piece of the hull showed an abnormal amount of inclusions.

I thought one of the reasons for the various damascus and laminated patterns was to minimize the effects of the flaws in each individual strand of metal.

Thanks Chuck H for taking the time and showing the ductility figures.