.

Anyone Else Still Lap?

p3skykingp3skyking Member Posts: 25,750
edited May 2017 in General Discussion
A friend brought me a Mosin 91 he had bought at an auction.
The bore looked like a rutted dirt road and he wanted to know if anything could be done.
Being .30 caliber I told him about lapping. I have several M-14 steel cleaning rods so lapping it was.

I pour a molten lead plug at the muzzle and coat it with valve grinding compound. After the first pull I can tell if the barrel is still usable and if I should go to a bigger grit paste.

The lad lucked out. There were no excessive tight or loose spots in the whole length of the barrel. We met at the range two days later and the gun could still put everything within 5 inches at 100 yards.

Back in the 70's I think, maybe 80's, someone came up with fire lapping. I never really cared for that because you may be abraiding a barrel that doesn't need it. You don't know unless you can feel the plug move the whole length of the barrel.

It's nice to be able to save the original barrel when you can.

Comments

  • bpostbpost Member Posts: 30,977 ✭✭✭✭
    edited November -1
    I use the non embedding JB bore paste with a lot of Montana extreme to get fouling out. Kroil and JB bore paste go together like peanut butter and Jelly too!
  • Sam06Sam06 Member Posts: 18,925 ✭✭✭
    edited November -1
    quote:Originally posted by bpost
    I use the non embedding JB bore paste with a lot of Montana extreme to get fouling out. Kroil and JB bore paste go together like peanut butter and Jelly too!


    JB's has squared away a lot of my old rifles.

    I have never done what you describe. I have used a very fine Valve grinding compound one time to work on the bore of a 32-20 SS rifle that was a little rough. It worked well on a tight patch.
    RLTW

  • p3skykingp3skyking Member Posts: 25,750
    edited November -1
    quote:Originally posted by Sam06
    quote:Originally posted by bpost
    I use the non embedding JB bore paste with a lot of Montana extreme to get fouling out. Kroil and JB bore paste go together like peanut butter and Jelly too!


    JB's has squared away a lot of my old rifles.

    I have never done what you describe. I have used a very fine Valve grinding compound one time to work on the bore of a 32-20 SS rifle that was a little rough. It worked well on a tight patch.


    That's kind of the same principle, but the lead plug doesn't alter size in the barrel giving you a true picture (by feel) of the barrels condition. By lapping with the lead plug and abrasive, you make the entire length of the barrel uniform, the same size as the bore at the muzzle.
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