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Thread: Counterboring a barrel

  1. #1
    Boolit Master fourarmed's Avatar
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    Counterboring a barrel

    My nickel steel Springfield has a fragment of steel ironed into the bore surface about three inches back from the muzzle. I am reasonably sure it is steel, since electrolytic cleaning didn't touch it and fire lapping did almost nothing to it. Does anybody have any advice about trying to counterbore back far enough to remove it? I know I would need a piloted drill or reamer to have any hope of accuracy. What size bit would be advisable?

  2. #2
    Boolit Grand Master
    Mk42gunner's Avatar
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    In theory a 5/16 drill will cut a .3125" hole, and that may be big enough.

    The only thing I have ever counter bored is a Type 38 Arisaka in 6.5x.257 Roberts that had an unfortunate run in with a mud dauber. The barrel was already pretty short and I couldn't have cut it and stayed over the legal limit so I tried counter boring.

    Robert

  3. #3
    Boolit Master

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    How does the rifle shoot the way it is? How did you discover the presence of the inclusion -- with a bore scope? Is re-barreling an option? Mk42gunner is correct about the drill bit size, but in foreign military rifles I've encountered that have been counter-bored the hole was usually proportionately larger to the bore size, notably in Czech VZ-24s and Mosin Nagant rifles. Of course, , maybe that was the only drill bit they had! I have a VZ-24 re-bore that shoots fantastically well.

    It sounds like your Springfield is in "as-issued" condition, so I can understand the desire to retain the original barrel for authenticity, but there's just something about reboring barrels that gives me the willies, and by doing so you lose authenticity right there. On the other hand, many if not most Springfields were re-barreled at one time or another, so having one with a different than original barrel is not inauthentic.
    DG

  4. #4
    Boolit Grand Master Texas by God's Avatar
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    If it shoots well, I would just leave it alone and ignore that little blemish.
    Otherwise you might take a 30 carbine finish reamer and braze a tool Rod extension on it to give you the length needed to clean that area up.

    Sent from my SAMSUNG-SM-G930A using Tapatalk

  5. #5
    Boolit Master fourarmed's Avatar
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    This rifle still has the original barrel, and is in more or less original condition. If I could get it to shoot well without rebarreling, that is what I want to do. Rebarreling would be a last resort. In fact, I would probably sell it rather than go that route. I don't shoot high power any more, and I have lots of good-shooting rifles to occupy my old age.

    I have looked at the inclusion with a bore scope, although I spotted it shortly after I bought it with the unaided eye. I like the carbine reamer idea. Thanks.

  6. #6
    Boolit Master

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    I think Manson or Clymer make reamers to counterbore muzzles. Check with them or possibly one of the reamer rental places to see if they have one.

  7. #7
    Boolit Master
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    Three inches back from the muzzle?......how does a counterbore remove that?.......you will end up with a two diameter barrel...ruined...and next step a 21" barrel,or less.......Any originality or collectability is gone out the door...Leave it alone,and stop worrying.

  8. #8
    Boolit Master
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    get a core drill 5/16 have a pilot ground on it the you have a bit to counter drill it. a regular 2 flute drill is flerting with disaster so is the reamer idea.

  9. #9
    Boolit Master
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    1st place- muzzle cntbrs won't go as deep as you need. 2 place- see if you can find a machinist to pull barrel and do it in a lathe, centered on the bore, NOT the outside contour. I have had a couple done in bigger bore, 43 Spanish and 45-70. Both went from useless wall hangers to ram killers. If you can't find some one, maybe look into piloted chamber reamers so you get it to center on bore. I would shoot it a lot first.

  10. #10
    Boolit Master
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    Wil you be able to use anything piloted with an imbedded piece of steel in the bore?
    Aaron

  11. #11
    Boolit Master
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    Quote Originally Posted by ascast View Post
    1st place- muzzle cntbrs won't go as deep as you need. 2 place- see if you can find a machinist to pull barrel and do it in a lathe, centered on the bore, NOT the outside contour. I have had a couple done in bigger bore, 43 Spanish and 45-70. Both went from useless wall hangers to ram killers. If you can't find some one, maybe look into piloted chamber reamers so you get it to center on bore. I would shoot it a lot first.
    I counter bored an IAB sharps 45/70 to clean up a rust spot that was leading - did it in the lathe - seemed like it worked but there was another rust spot further in and at the end I hacked the barrel, recrowned it, and recut the front sight dovetail - should have done that in the first place. Guns that wont shoot have zero value (to me) so if someone with more money than sense wants to hang it on the wall - I say sell it

  12. #12
    Boolit Master RU shooter's Avatar
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    Since it's only 3" from the muzzle could you possibly lap or broach cut just that tiny area ?sorta how they fresh a old black powder barrel but possibly you could only fresh that one groove in a very small area . I assume it's in the groove ? I'm not sure how a counter bore 3" deep would shoot ? deepest I have seen was a old Finn 91/30 I had counter bore was about 1.5" shot great though.
    If you find yourself in a fair fight, your tactics suck!

  13. #13
    Boolit Master
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    Quote Originally Posted by joatmon View Post
    Wil you be able to use anything piloted with an imbedded piece of steel in the bore?
    Aaron
    he shot the gun yes? fire lapping etc. I'm thinking might work....maybe not, gotta find the right cartridge.
    the barrel is steel
    IMHO- anything you try that involves any tools of any sort--short of a lathe or possibly a milling machine will end badly. And you will find a gunsmith/machinist to counterbore it anyway to fix your f### up, foul up, did I say foul up. Might just shoot it a lot. I have guns with big problems somewhere in the bore (not crown) and they shoot well enough
    have fun

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