doublegunshop.com - home Forums General Discussion DIY Gunsmithing @ doublegunshop.com dent repair in shotgun barrel

have purchased an extra set of barrels for a stevens 311 in 410. one of the barrels had a dent about 8" from the muzzle end and needs to be raised ect. have had several dent removed from 12 ga barrels and have been satisfied with the results. am aware of the metal slug and the screw expander device used inside the barrels to raise the dent and recontour ect. the 410 barrels appear to have thicker metal than say a 12 ga barrel and want to know how well dent removal works when it is used on 410 barrels. anyone out there have any experiences they can share on 410 barrel dent repair?

I do not have any dent removal experience with .410 bore barrels, but have removed dents in 20 ga. barrels. I can't say that was any more difficult than raising a similar dent in a 12 gauge barrel. Considering that your dent is about 8" from the muzzle, I don't imagine the wall thickness there would be so thick as to make dent removal all that difficult.

Some years back, I built a hydraulic dent raising tool and used 1/2" EMT conduit to test it out. The wall thickness of the galvanized steel EMT was .042". I could make some pretty healthy dents in it, and then easily raise them with the hydraulic pressure of the anvil alone. I know jacking a dent up with hydraulic pressure is NOT the proper way to use a hydraulic dent raising tool, but I wanted to see what it was capable of. I was able to easily produce over 3000 psi of pressure. It was evident that a hydraulic dent raising tool used this way could easily turn a dent into a bulge, even with steel tubing thicker than the average forward portion of a shotgun barrel.

So in short, I wouldn't over-think it or worry that it can't be done. It doesn't take a whole lot of force to dent a shotgun barrel, and it doesn't take a whole lot of force to remove that dent either.

thank you for the reply. have did little work on 12 ga dents. the barrel thickness looked to be "thicker" on the 410 barrels than a 12 ga. with no experience on a 410 was looking for suggestions. my method will be using sized slugs inside the barrel, brass hammer and aluminum tape for a pad.

Aluminum tape works well for that, in my experience. I've never done it on a .410 either, but I think you can do it even with the thicker barrel walls. May require more time and patience, and hammer "pecks".

I am fortunate to have a small metal lathe to make plugs for removing dents and other things. What I do is measure the internal diameter of the barrel right before the dent, (since there are no gages to measure a.410 you could use a plug diameter of .410 and see if that fits and go from there. There are a few companies that make hardened plug gages but they do no have a beveled edge and I would not try them in the bores of any gun. I then make a tapered plug so that the front taper passes under the dent and the main body of the plug is .001-002 smaller that the diameter of the barrel. On the back end of the plug I drill and tap for 1/4x20 so that I can thread a rod into it. I then heat the barrel with a propane torch till warm and then tap the plug till it goes through the dent area.
You can also leave plug where it gets tight in the barrel and tap the outside with a small fender hammer, the one with the large flathead. Like stated by Keith I have never done a .410 but shouldn't be any different than any other guage.

Is the heat required? To me it seems you wouldn't get it hot enough to affect the steel ,,and if you did you would have trouble with the solder melting I have never used heat

No, not required. I've removed several dents with plugs, and also with an expanding mandrel type device, but always using a very small hammer. I've never used heat.

On another forum years ago the conversation was on dent removal and I had replied on a question about what I do. A gentleman replied that he was a gunsmith for 40 years and he suggested to apply a little heat in the area of the dent, just enough to get it warm. His theory was that in doing so you were moving some of the molecules of the steel around and would help in raising the dent. Ever since then I have used heat on any gun I get that has a dent or so. Never enough heat to melt solder which is about 450 deg. just warm to the touch.

Interesting, David. Can you offer a comparison on how it works with a little heat as compared with how you previously did it with no heat?

Well Mr Williamson I'll give it a try I have hydrolic and I make metal slugs but I have never tried heat

Stan, it seems without using the heat it took longer to take the dent out. Using the heat then putting the plug in and tapping the end of the rod the dents seem to come out and most times do not have to use the hammer.
Here are a few pictures of a 10 g. L.C. Smith.

[img]https://i.imgur.com/Ibr3LUB.jpg?1[/img]

Barrel reblued and etched.
[img]https://i.imgur.com/IzoKhaD.jpg?1[/img]

I cant figure out why the other pictures were not copied but click on them and they will open

Thanks, David. Nothing like a good picture. If I ever have the need to remove another dent I will try some heat from a propane torch. Anything that would speed the process, and do no harm at the same time, would be beneficial. I assume you oil the plug lightly to help prevent any galling of the barrel?

For David

Barrel reblued and etched.


Remove the ?1 from the string

Stan, I do not put any oil on the plug. The only oil that is there is a light coat from storage. On the 10 ga. the plug was .773 and the bores were .750. I have made aluminum plugs for 10, 12, and 16 gauges as a go/no go fit.

These naturally are for 12 ga. The smallest at .724 is for some 12 gauge L.C. Smith hammer guns that have a smaller bore. Have never run across an L.C. Smith hammerless that small in diameter.

Thanks Mike, I use Imgur as a photo hosting site and when I want to post a picture I click on BBCode and click on copy. Most times it works great.

Also wanted to mention Happy Thanksgiving to all.

For those that don't have the equipment to make their own plugs you can buy "GAGE PIN SETS" that can cover a range of bore IDs. I have two sets: .501" to .625" and .626" to .750" (Increments in .0001"). These will cover 28 thru 12 gauge barrels. Cost when I purchased was about $70 a set shipped.
Bob Jurewicz

Bob, they are good for getting bore diameters, not good for use as plugs for removing dents because they have no beveled leading edge and could score the barrel. They are made of hardened steel.
Plus I think you meant to put .001 instead of .0001. They would have to be centerless ground for that tolerance and it would cost a lot more.

Jent Mitchell posts on here sometimes and he bought set and took them to a machine shop to have a level put on them, cost a lot more than the plugs.

Should have mentioned that I do bevel the edges.
Bob Jurewucz

I have a couple sets of pin or plug gages that were made with a slight bevel, so they can be used for barrel dent removal work without causing further damage to the bore. They are also .501" to .625" and .626" to .750". However, as David notes, many sets are not beveled, and would need to be altered for use as dent removal plugs.

Although I've never tried using heat to aid in barrel dent removal, I can believe it would work. I clearly recall learning about how steel properties can change significantly with minor heating when I first started working at a steel mill. I was working on a Slitter, which was used to slit roughly 60" wide coils of flat rolled steel weighing upwards of 20 tons into narrow strips of various widths. One order we had for a few thousand tons was some high carbon high alloy steel that was very hard and springy. It was during a severe cold spell when outdoor temperatures were around zero degrees F, and it wasn't much warmer inside the mill. This particular steel alloy was giving us fits because it was chipping on the slit edges, creating quality issues, and the scrap kept breaking like an icicle. In fact, I still have a small hairless scar on my right shin from the scrap strip breaking and springing back, and slicing into my leg.

Apparently, they had this problem in the past, because it was decided to fire up the gas burners under a large insulated tank of water, and heat it to near boiling. When it was hot, the overhead crane would set ice cold coils into the hot water and let them simmer for hours. After the steel was heated by perhaps 150 degrees or so, it behaved like a different animal, and ran through the Slitter much better and easier. Of course, this extra heating step was troublesome and consumed a lot more time, so we were happy to finally finish that order. But it taught me that steel properties can change quite a bit at temperatures far lower than we typically associate with annealing, heat treating, or tempering.

On the other hand, there was another alloy we made that was called helmet stock or grenade steel. It had been used to make Army helmets before they changed to Kevlar. It was also used to make cluster bombs, and a pattern was rolled into it by Defense contractors to help it fragment into small pieces of shrapnel when the bombs or grenades detonated. That stuff was extremely brittle and would sometimes shatter even when it was still glowing red hot as it was being coiled up coming off of the Hot Mill. The many holes in the sheet metal walls at the Downcoiler end of the building told you that it wasn't a safe place to be when we were running grenade steel.

Hi Guys,
Just to inform you the manufacturer of the Original English Hydraulic Dent Raiser is:-
Desman Engineering Ltd,
Burma Road,
Blidworth Industrial Park.
Blidworth,
Nottinghamshire.
NG21 0RT.
United Kingdom.
https://www.desman-engineering.com/
Phone
Simon 01623 499962 or Mark 01623 499968
email, Sales@desman-engineering.co.uk
Simon@desman-engineering.co.uk
Mark@desman-engineering.co.uk
Any questions please don't hesitate to contact us.
Regards

Very useful information. Thanks.