Lapping a Barrel?

Discussion in 'Gunsmithing' started by kc, May 16, 2011.

  1. kc

    kc Well-Known Member

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    I got my fat little hands on a real nice 03A3 Springfield, it wont shoot for crap(realy) it cant even hit the black at 50yards, I was thinking after shooting it a bit things might change, no I fired about 30 rounds and I have been using JB Lapping Compound, I have used a half of my patches scrubing and brushing, an old friend told me, if you need to get tough use some Rubbing compound.
    Its starting to clean up some areas there was some bad spots in the grooves and its just starting to shine. its a 1947# how much scrubing is to much?
    Its kicking my but and I am just about had it. At first I could run a patch and the rod would not rotate and its just starting to. its just filthy and what looked like pits are disapering.

    Any advice could help..Thanks.
     
  2. Gunpoor

    Gunpoor Well-Known Member

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    First, just to clear the air, I am no expert. That said, I have hand lapped a couple of rifle barrels. The way I lap them is to get a soft/swaged lead bullet just larger than groove diameter and a wooden dowel rod that will fit through the bore of your project rifle, the larger the better as long as it fits, and some lapping compound (valve grinding compound might work but I have never used it). Push the lead slug through the bore from the breech end and remove it at the muzzle end. You will probably encounter quite a bit of resistance because it is engraving the slug to the rifle bore. Then put some lapping compound on the shaped slug and push it through the bore the same direction as before but hold the barrel end against a non-marring surface so the slug doesn't exit the barrel. Then push it through the bore from muzzle to breech. Repeat this process continually and occasionally add more lapping compound until the bore is polished to your satisfaction. The last rifle I hand lapped went from a fairly accurate rifle to a one-ragged-hole shooter that hardly leaves any guilding material in the bore after 25 fired rounds. BTW, I don't use bore brushes in my rifles when cleaning just foaming bore cleaner and cotton patches.
     

  3. kc

    kc Well-Known Member

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    I have been scrubing the living hell out of this barrel I have been running a bore brush than an oiled patch and its filthy, I am using sweets 7.62 and every patch is blue and it has never changed...I cant believe the fouling, I have a mop that soaked with this solvent I let it set , than run a clean patch and its all blue, I run an oil patch and its filth..so far its been 4 hrs of cleaning this barrel and its so loaded I can understand why it shoots so bad.
    Have any of you guys ever encounterd a rifle with this fouled of a barrel?
    I am thinking of pluging the barrel and let it soak over night.
    Or I was thinking the chrome lineing in the barrel has been destroid.
     
  4. Fitch

    Fitch Well-Known Member

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    When you get it cleaned up enough, if it will clean up, locate a borescope and take a good look. I hope yours isn't one of those that was fired with corrosive primer military ammo and not cleaned for a while. That completely destroys a barrel - pits it so bad it's almost impossible to get it clean..

    Fitch
     
  5. Bullet bumper

    Bullet bumper Well-Known Member

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    Are you sure you are seeing blue on your patch because of barrel fouling or because the sweets is disolving your bronze brush? Apply some sweets with a nylon brush or patch , leave it a while and then just patch it out . Do that a few times to see if copper color persists. If it stops you where disolving your bronze brush . If it don't you may have multiple layers of copper fouling .Or fouling in corrosion pits which can't be cleaned out properly by normal cleaning.
     
  6. shortgrass

    shortgrass Well-Known Member

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    I've never seen a chrome lined 03-A3 barrel. I wouldn't use Sweets over night. Might soak it up good with Butches and set it muzzle down on a rag. And 'Fitch' is right, you may end up with a barrel that's been fed and left after shooting corrosive ammo. It'll take some time.
     
  7. Bullet bumper

    Bullet bumper Well-Known Member

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    That is not a real good way to lapp a barrel. The lapping slug is way too short and if you have to remove it from the bore to load it then you may have lost it's correct groove position. A better way is wrap some tape around a cleaning rod just below the cleaning jag thread so that it will just slip into the bore and seal the bore. Put an old cleaning jag on the rod a smaller caliber than the bore is good. Insert the rod in the bore from the chamber end. Stop the jag about 1/2 inch from inside the muzzle . Then melt up some wheel weights or other fairly hard lead alloy and poor it into the end of the barrel but not let it overflow the muzzle end . Let it cool. Then push the rod up the barrel untill the cast lapp is halfway out the muzzle . Then load it with lapping paste and pull it back and forth but never letting it come out of the bore. Lapp less at the muzzle end than the chamber end. Don't overdo it or the barrel could be ruined.
     
    Last edited: May 17, 2011
  8. Coyboy

    Coyboy Well-Known Member

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    Are the bullets going thru the target canted or sideways?

    I suspect that barrel is to far gone to be any good, and scrubbing the hell out of it with abrasive isn't going to help matters any.

    If the barrel was rusted and pitted and you scrub with a bronze brush and oil thats fine, you are removing the bad stuff, rust ect.

    But using a metric ton of abrasive is going to remove the good steel that remains, and by the sounds of it you have very little to spare.:rolleyes:
     
  9. MTBULLET

    MTBULLET Well-Known Member

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    Take it to someone that has a bore scope and knows how to use it.
     
  10. J E Custom

    J E Custom Well-Known Member

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    Lapping a barrel correctly is almost a art form because there are so many ways to screw one
    up that it is not recommended unless you realy know what you are doing.

    In your case you are trying to save a barrel that was fed a steady diet of corrosive ammo.(Ammo
    was corrosive until 1953 to 1955) so it is probably pitted as the others have said.

    There are many reasons that the rifle may not shoot and the barrel could be one of them
    but stock to action/barrel fit may be another.

    The bore scope is almost a must in these situations because looking down a barrel with a bore
    light normally only tels you that it is clean or dirty, The bore scope looks at the bore 90o to
    the rifling and will give a much better view of the condition of the barrel.

    There is another way to bring an old barrel around and that's with a bullet swage that can
    make over sized bullets. (.308 to .309) I have seen some match rifles that had been shot
    thousands of times come alive when fed over size bullets.

    Also with very little rifling left in a barrel sometimes the lighter bullets work better, so try
    a much lighter bullet.

    I would not clean the barrel any more if it is pitted and let the copper fill in some of the pitting
    and if there is enough rifling left it may do better.

    Just some things to try.

    J E CUSTOM
     
  11. Fitch

    Fitch Well-Known Member

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    That's an excellent question. My wife's sporterized '03, which was ruined by corrosive primers sometime before we were married, put bullets sideways through the target at 50 yards (the farthest away we could even hit paper with it).

    Barrels that have been ruined by corrosive primers are not salvagable in any practical sense.

    I rebarreled my wife's rifle.

    Fitch
     
  12. kc

    kc Well-Known Member

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    I got it cleaned today I worked another two hrs, I put the Barreled Action in the rince tubs and used the bore brush and used some dry cleanser and not I have no blue patches just a real clean barrel. I did noticed when I went half way, I found an area that is real easy to push the patch..I think its bulge in the center of the barrel.


    Thanks for all your input.
     
  13. Fitch

    Fitch Well-Known Member

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    You might consider slugging it if you can't find a borescope someplace.

    Fitch
     
  14. kc

    kc Well-Known Member

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    I have accsess to a Borescope, my friends have have two, both are gunsmiths, its a good idea and I will check it out..I need to finish this rifle its worth a few bucks I can turn a proffit but I just cant see myself selling it. Douglas has a barrel both in stainless and regular steal both and are air gage chamberings cut (matched) for the Springfield Rifles $310.00 and they are high quality.