Fixing a bulge in a shotgun barrel

05 May 2022, 00:20

I recently picked up a Winchester model 12 20 gauge.
It has ring bulge in the barrel about 6 inches back from the muzzle.

Is anyone on this forum familiar with fixing such a condition or those that do this type of work.

05 May 2022, 00:41

jimatcat

Kirk Merrington in Kerrville Tx... or take it to Brileys in Houston.. both have removed dents... bulge??.. maybe not...

05 May 2022, 04:02

custombolt

Roy from Memphis says he removes bulges.

bulge removal

05 May 2022, 20:09

Duane Wiebe (CG&R)

A rib complicates matters. Years ago, I took an idea out of some gunsmithing book:

A pipe cutter with all rollers! With a rib, just have to take if off and re set after repairs.

06 May 2022, 00:10

richj

mmm parallel roller with an insert.. and where do you get one.

quote:
Originally posted by Duane Wiebe (CG&R):
A rib complicates matters. Years ago, I took an idea out of some gunsmithing book:

A pipe cutter with all rollers! With a rib, just have to take if off and re set after repairs.

06 May 2022, 06:05

Nick Hughes

quote:
Originally posted by Duane Wiebe (CG&R):
A rib complicates matters. Years ago, I took an idea out of some gunsmithing book:

A pipe cutter with all rollers! With a rib, just have to take if off and re set after repairs.

I did this once. Still have the cutter with the smooth rollers. I failed though....the barrel cracked. Perhaps if I had heated it somewhere along the way to soften it up it would have worked. It did roll the bulge out well. If I remember I made a slug to go in the bore to prevent it from collapsing. Not to give up I cut it off, soldered another piece of barrel on the end, reamed and honed the bore.

06 May 2022, 09:26

2152hq

Bbl bulges sometimes crack when pushing them back into shape. The metal has been pushed beyond some stess point that I don't understand as I am not a mechanical engineer nor pretend to be.
I think the metal is already cracked whne bulged many times though it can't be seen with just a plain visual examination.
Hammering or otherwise pushing it back into place doesn't do anything for strength. It can look nice though.

Heating them (stress relieving(?) and then pushing them back into shape would likely have a better chance at success if not already cracked.

I saw a set of AH Fox bbls with a bulge just in front and at the bottom of the rt chamber repaired by a so called restoration master.
Easy fix he proclaimed..

The bulge was cold hammered back into place,
The bore & forcing cone polished out and the outside damage and hammer work refinished.

Once the bbles were re-rust blued, the damaged area was hard to pick out unless you knew of it before hand.

The right bbl burst on the 2th round.

06 May 2022, 20:29

Duane Wiebe (CG&R)

Metallurgists client brought me up t o speed on "elasticity" Example is paper clip...three sheets of paper will not stretch the metal beyond coming right back to original shape

Go to the point where the paper clip does not return to original you're beyond elasticity and on the way to failure.

Same thing must happen in a bulged barrel..not sure how you determine if that happened, but a safe alternative is to anneal, slightly reform and anneal again as judgment calls for and anneal after final shape is attained.

Never tried to heat treat afterwards..beyond my pay grade, but believe it safer not to even try . A bulge at the chamber or very close would give me pause

06 May 2022, 21:59

ledvm

quote:
Originally posted by Duane Wiebe (CG&R):
Metallurgists client brought me up t o speed on "elasticity" Example is paper clip...three sheets of paper will not stretch the metal beyond coming right back to original shape

Go to the point where the paper clip does not return to original you're beyond elasticity and on the way to failure.

Same thing must happen in a bulged barrel..not sure how you determine if that happened, but a safe alternative is to anneal, slightly reform and anneal again as judgment calls for and anneal after final shape is attained.

Never tried to heat treat afterwards..beyond my pay grade, but believe it safer not to even try . A bulge at the chamber or very close would give me pause

That parameter is known as the elastic limit.

The bulge in it’s own means the elastic limit was exceeded.

Think of a 30” waist pair of shorts that going on and off the person that they were meant to fit…versus putting those same shorts on a 40” waist person — they never return to 30” again…they were plastically distorted due to their elastic limit being exceeded.

Barrels stretch as a load goes through with each shot. This stretch, more correctly termed barrel strain, is commonly measured in pressure testing with strain gauges fixed to the barrel.

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07 May 2022, 04:18

Russ Gould

Bulges are fixed all the time. With a small hammer and a mandrel. Heat helps a bit but you really need a LOT of heat to reanneal the metal and special cooling regimen. Then ream and hone. Reblack. Not worth it for a Model 12, it will cost more than the gun is worth to do it right.\

There isn't any pressure to speak of at that point in the barrel.

And yes it may crack if the bulge is big.

07 May 2022, 04:38

JonP

Sent one to Keith Kearcher years ago...came back perfect.

07 May 2022, 08:12

ledvm

quote:
Originally posted by Russ Gould:
Bulges are fixed all the time. With a small hammer and a mandrel. Heat helps a bit but you really need a LOT of heat to reanneal the metal and special cooling regimen. Then ream and hone. Reblack. Not worth it for a Model 12, it will cost more than the gun is worth to do it right.\

There isn't any pressure to speak of at that point in the barrel.

With respect…it took pressure to create the bulge to begin with. Maybe there was a dirt-dobber’s nest in the barrel.

And yes it may crack if the bulge is big.

09 May 2022, 11:39

Peter Connan

Bore obstructions can significantly alter where in a barrel pressure exists.

But no firearms are designed to survive muzzle obstructions.

As for why they crack, it's less a matter of exceeding the elastic limit and more a question of what the ductility of the material in question is.

The aforementioned example of the paper clip: A couple of sheets of paper and the clip returns to it's original shape when they are removed.
Shove it over a thick pile of paper, and it bends. But it doesn't break. However, if you bend it repeatedly in the same place, it will eventually break. But the wire they are made from is very ductile.

Make the same paper clip from a piece of high-speed steel and it will require a lot more force to bend, but it will also break much sooner if bent.

09 May 2022, 12:02

georgeld

Not gun related.

I worked for Cleaners Hanger Co. years ago.

Take any clothes hanger and twist the hook slowly.
It should twist off at 1 1/2 turns. Try it and see.

Very interesting subject when you get into tempering steels.

George

09 May 2022, 18:37

Lester Brooks

Here is a tool designed and made back in the 1960's to measure the chambers and chokes of all gage shotguns. In ten seconds you could tell if the choke had been altered or see if you had a swell in the chamber to the end of the forcing cone. There weren't any quick ways to see what was inside the barrel. I will posts pictures and a drawing of dimensions. This tool will work on 410-10 gage barrels by bend the end to fit inside and then set the dial to zero. As you move the reading on the dial will tell you the diffenence between the bore dia. and the section you need to know. If you want the true diamenter we had a 3 ft long mic that you could get the true diamenter. My designed tool would make a quick determination as you need to know the different in the bore and choke diamenters. It may take a couple of posts to get this posted. After inserting the prongs into a barrel ZERO THE SETTING BEFORE REMOVING AND SEE THE READ OUT ON THE DIAL. We checked the reading with a long mic and compared the results by measureing across the small prongs of me tool and found that it would be about .001 difference.

09 May 2022, 18:42

Lester Brooks

My drawing made in 1993

09 May 2022, 18:57

Lester Brooks

The above tool has nothing to do with a swell in the barrel. Our shop would not try to compress the steel back into a large bulge, but would hammer out small dents. This tool was used lots of times and made a great deal of money quickly. I made of couple of these tools for gun show traders to find out if a shotgun barrel had been altered before they would pay fare prices for a trap shotgun. If the barrel is long enough we could cut off and install Polychokes.

The prongs could be bent to fit any barrel and the amount of pressure on the dial indicator was so light that it didn't make any difference

11 May 2022, 04:40

Atkinson

Ive seen a couple of older guns that were repaired with bulges that have been shot for years according to the owners!! I, personally would replace the Barrells, on most factory shotguns and would not buy one, I have a policy not to buy someone elses problems if I can help it...

11 May 2022, 05:23

custombolt

I sure hope Timan gives us an update in the next week or two. Which choke is on the barrel Mr. Timan?

A question for all ---- Would a full choke barrel be most prone to developing a bulge near the muzzle?

12 May 2022, 23:44

Russ Gould

quote:
With respect…it took pressure to create the bulge to begin with. Maybe there was a dirt-dobber’s nest in the barrel.

That type/location of bulge is usually the result of an obstruction or overchoke and it's the lead that causes the problem, not the gas. With respect.

14 May 2022, 17:42

Timan

quote:
Originally posted by custombolt:
I sure hope Timan gives us an update in the next week or two. Which choke is on the barrel Mr. Timan?

A question for all ---- Would a full choke barrel be most prone to developing a bulge near the muzzle?

It's a full choke and the barrel is stainless with a full length rib.

14 May 2022, 21:11

Fal Grunt

I went through this recently with a customer who had an expensive pre-war Sauer that had a minor bulge in the barrel.

A friend of mine is a master gunmaker from Germany who works on shotguns extensively. He called around to see if anyone would be willing to take it on. The short version is that unless you are willing to spend a significant amount of money, it is not worth fixing.

15 May 2022, 04:24

custombolt

Timan,

Did you ever call this shotgun barrel guy?

shotgun barrels and stocks

I think the gun is worth saving if it is one made in the late 20's.

quote:
Originally posted by Timan:
quote:
Originally posted by custombolt:
I sure hope Timan gives us an update in the next week or two. Which choke is on the barrel Mr. Timan?

A question for all ---- Would a full choke barrel be most prone to developing a bulge near the muzzle?

It's a full choke and the barrel is stainless with a full length rib.

16 May 2022, 00:59

Duane Wiebe (CG&R)

Stainless? Are you positive? That would be a new one on me

16 May 2022, 03:20

squeezenhope

It's worth millions! One of kind. Well, maybe not millions.

16 May 2022, 17:31

Timan

The barrel is stamped stainless, in where all the rest of the markings are near the breech end of the barrel. Is this unusual?

16 May 2022, 17:55

squeezenhope

I apologize, I let my mouth out run my brain. Dave Riffle's book notes that Stainless Steel was offered as an "extra" in the 1925 catalog. It was subject to an additional charge. Additional quotes, "Problems and complaints were pouring in regarding the stainless steel barrels"(1928). " The problems persisted with the stainless steel barrels, causing sales to rapidly decline" (1929). It appears that the complaints revolved around finish.

16 May 2022, 18:04

Timan

apparently, the finish was called Japaned seems to be some form of coating, which is mostly intact on this gun.

16 May 2022, 18:19

Timan

I'm wondering if the bulge will grow if I shoot it like is and will this affect the pattern.

16 May 2022, 18:30

Timan

quote:
Originally posted by custombolt:
Timan,

Did you ever call this shotgun barrel guy?

shotgun barrels and stocks

I think the gun is worth saving if it is one made in the late 20's.

quote:
Originally posted by Timan:
quote:
Originally posted by custombolt:
I sure hope Timan gives us an update in the next week or two. Which choke is on the barrel Mr. Timan?

A question for all ---- Would a full choke barrel be most prone to developing a bulge near the muzzle?

It's a full choke and the barrel is stainless with a full length rib.

Yes I did but his voice mail just says call back no messages, probably catch him eventually.

17 May 2022, 00:34

Kolo-Pan

Since there are so many Winchester model 12 shotguns out there but they aren't being made anymore I wonder why some of the extremely talented gunmakers don't make barrels and other parts that wear out for them.

17 May 2022, 02:54

custombolt

For Duane - Model 12 with SS barrel.

17 May 2022, 03:39

Duane Wiebe (CG&R)

WEll...Son of a gun...would have bet a big mac on this! Thanks much!!

17 May 2022, 04:40

custombolt

No problem DW,

For what it's worth, most of the ones I've seen offered or sold online in the last 15 years were circa 1927 and had the solid rib. Polished barrel examples seem to bring a few hundred more than black coated ones in similar condition.

Good luck Mr. Timan.