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Lapping a Barrel?

 
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  #1  
Old 05-16-2011, 05:50 PM
kc kc is offline
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Lapping a Barrel?

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.
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Old 05-16-2011, 07:29 PM
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Re: Lapping a Barrel?

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.
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Old 05-16-2011, 08:34 PM
kc kc is offline
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Re: Lapping a Barrel?

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.
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Old 05-17-2011, 05:16 AM
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Re: Lapping a Barrel?

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
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Old 05-17-2011, 06:46 AM
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Re: Lapping a Barrel?

Quote:
Originally Posted by kc View Post
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.
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.
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Old 05-17-2011, 06:51 AM
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Re: Lapping a Barrel?

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.
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Old 05-17-2011, 06:56 AM
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Re: Lapping a Barrel?

Quote:
Originally Posted by Gunpoor View Post
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.
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 by Bullet bumper; 05-17-2011 at 07:00 AM.
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