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Deburring a shortened shotgun barrel?

Discussion in 'Gunsmithing and Repairs' started by Tallinar, Nov 13, 2017.

  1. Tallinar

    Tallinar Member

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    Hello all,

    I am planning to spend some time working on an old single-shot 12 gauge this winter, and I'd like to shorten the barrel length so that it's cylinder bore. I've been reading through various posts on the web and these forums, and I am confused about a particular step.

    I am planning to simply use a hacksaw and a vice and/or miter box to make the cut. Once I am done, I understand I will need to file and sand the outer "face" of the barrel mouth. However, when it comes to deburring the "inside" of the barrel mouth, I am not really sure what technique to use.

    What tool and method do you suggest using for deburring the inside of the barrel mouth? Is it something that can be done with simple sandpaper? Do I stick a file in there, or does that risk creating uneven surfaces? Do I need some sort of reaming tool to ensure a uniform shape? What do you guys suggest?

    Product links are appreciated, as I am pretty uninitiated at this kind of stuff, and visuals would help. Thanks for your time.
     
  2. easy

    easy Member

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  3. Ohen Cepel

    Ohen Cepel Member

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    Debur it gently with a file or the correct sand paper. I would then use a large marble with polishing compound on it to finish it off. Cold blue when you're happy with it and enjoy.
     
    JeffG likes this.
  4. Tallinar

    Tallinar Member

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    Thanks guys!
     
  5. MachIVshooter

    MachIVshooter Member

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    Well, I chamfer them slightly with a 120° carbide tool bit, but I'm guessing you don't have a lathe, so............rat tail file ;)
     
  6. Sunray

    Sunray Member

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    Don't use a hacksaw. Use a pipe cutter then a half round file on the muzzle, inside and out, to deburr. Takes less than an hour start to finish. Any sand paper will take eons too.
    And don't buy anything on E-Bay. They fund the people who want to take your shotgun away from you
     
  7. edwardware

    edwardware Member

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    I too used a pipe cutter to good effect. Last time I mentioned that, some of the old hands pointed out that since the barrel is tapered the pipe cutter shouldn't work. . . none the less it does work, and quite well. Starting it straight on a tapered cylinder is a hand skill, but not that difficult.

    I would deburr with whatever chainsaw file/rattail file you have on hand.
     
  8. dfariswheel

    dfariswheel Member

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    The old timer method is to just wrap some fine wet or dry sand cloth over the ball of your thumb and run that around the muzzle to break the sharp edge.
    Shotguns are not as critical as rifle or pistol muzzles.

    One trick to cut the barrel is to wrap a piece of tape around the barrel where the cut is to be. Keep the tape square with the barrel.
    Then use a hacksaw with a fine cut blade and make a one or two easy stroke cut on the edge of the tape.
    Rotate the barrel and make another shallow cut.
    Continue until you have a line cut all the way around.

    Then just continue making shallow cuts and rotating the barrel until it's cut through.
    This keeps the muzzle square and greatly reduces any needed filing.

    If you use a pipe cutter note that this will roll the edge inward and you'll have to file that off inside the muzzle.
     
  9. JeffG

    JeffG Member

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    +1 on the pipecutter. I deburred with wet or dry and a cue ball.
     
  10. MachIVshooter

    MachIVshooter Member

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    I'll have to respectfully disagree with this advise. Not only will the tool pressure constrict the opening, but the chain/channel will likely mar the barrel. You're also no more likely to get a true cut out of it.

    I use a Porta-band for all barrel shortening, then clean them up in the lathe. Except SCAR barrels. The case hardening done on those things eats band saw blades, so I use a cut off wheel for them.
     
  11. Tallinar

    Tallinar Member

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    Thanks for the advice folks. I ended up using the hacksaw method. I clamped the barrel to a miter box and just gave it the straightest cut I could, then put the barrel in a vice and used a file to try to square and smooth out the muzzle face. Using a deburring tool like the one easy had linked made quick work of the inside deburring. The whole process was actually much easier and more fool proof than I thought.

    My only remaining question now is this:

    With a cylinder bore shotgun, how important is it to have the muzzle crown perfectly square? I mean, at this point, it's pretty darn square to my eye, but probably not perfect. Will slug accuracy or shot patterning be dramatically impacted if it's not *perfectly* square? Unfortunately, I won't have a chance to get to the range and test this for several weeks, but if ya'll think good enough is probably good enough, I may go ahead and cold blue it this weekend.

    EDIT:
    Here are a couple pictures. Hard to try to show squareness in a picture, but at least it's something:
    https://i.imgur.com/xJ5XMHC.jpg
    https://i.imgur.com/4Rg69HJ.jpg

    Thanks again.
     
    Last edited: Nov 20, 2017 at 6:50 PM
  12. Scooter22

    Scooter22 Member

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    I did a old Stevens the same way. It looks good but I'd releive the inside edge a little more so theres not an edge. If you used a square and it looks true across the muzzel flat I wouldn't worry about it. Shot and buckshot aren't really going to be effected unless your really off. The rifled lead slugs are pretty forgivnig too. You don't have a target shotgun there. Just shoot it and see.
     

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