49willys
Member
Hello,quick question,when lapping a bore what do you use for compound?i have a jar of valve lapping compound,is that too aggressive?the jb bore cleaning paste doesnt seem to prevent copper fouling.
Lapping a bore
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Deaf Smith
Member
You can firelap the gun IF the bore really needs it.
You can google 'breaking in new gun barrel' for new barrels.
And 'firelap gun barrels' gets some good websites.
Deaf
You can google 'breaking in new gun barrel' for new barrels.
And 'firelap gun barrels' gets some good websites.
Deaf
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49willys
Member
I bought it used,barely used.it copper fouls real quick.
243winxb
Member
You want DavidTubb Final Finish Bore Lapping System. Its composed of a series of 50 bullets that are impregnated with 5 different progressively finer compounds.
Look for reviews on it.
Look for reviews on it.
Googling it is good. I've looked into it. Its quite possible to wreck the throat if firelapping too aggressively. There are many different grits or grades of lapping compounds.
There was a pretty good piece written by several guys on firelapping and handlapping on the Los Angeles Silhouette Club site (think thats correct) but it disappeared. It may be elsewhere online.
There was a pretty good piece written by several guys on firelapping and handlapping on the Los Angeles Silhouette Club site (think thats correct) but it disappeared. It may be elsewhere online.
If you are trying to polish (as opposed to truly lap) the bore to eliminate coppering up/-
make cleaning quick, use Tubbs Final Finish process.
You will get various opinions, but see also post #18 in this string:
https://thefiringline.com/forums/showthread.php?t=513700
make cleaning quick, use Tubbs Final Finish process.
You will get various opinions, but see also post #18 in this string:
https://thefiringline.com/forums/showthread.php?t=513700
243winxb
Member
Good link Mr Havey, thanks.
Several good comments.
I, unfortunately, have a rifle that I think needs to be lapped. It was bought used, and rebarreled to 260. Besides I think it never having the throat cut ( high pressure signs with starting loads), the gunsmith that looked at it said it was the roughest bore hed ever seen with his bore scope. After a good cleaning to remove copper, the groups go to pot after 10-15 rds, with a LOT of copper fouling in evidence.
Several good comments.
I, unfortunately, have a rifle that I think needs to be lapped. It was bought used, and rebarreled to 260. Besides I think it never having the throat cut ( high pressure signs with starting loads), the gunsmith that looked at it said it was the roughest bore hed ever seen with his bore scope. After a good cleaning to remove copper, the groups go to pot after 10-15 rds, with a LOT of copper fouling in evidence.
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49willys
Member
Thanks all,good info,just what i needed.
rcmodel
Member in memoriam
Lap with lead slugs screwed to a stiff rod.
Use 1,000 or finer grit grinding compound.
JB will work, it just takes longer.
Fire lapping takes out the throat faster then it wears away the rest of the barrel
Only the first few inches in front of the chamber get the worst of the fresh grit on each bullet.
rc
Use 1,000 or finer grit grinding compound.
JB will work, it just takes longer.
Fire lapping takes out the throat faster then it wears away the rest of the barrel
Only the first few inches in front of the chamber get the worst of the fresh grit on each bullet.
rc
I wouldn't lap a bore. Especially if you don't have the measuring tools to ensure you're doing it evenly over the full length of it.
Instead, shoot it a few times to lay enough copper in the rough spots low points, then no more copper will get removed from subsequent bullets.
Having shot a number of rounds of match grade ammo in rough bores of commercial and arsenal barrels, they all did quite well after half a dozen or so shots were fired through them. Clean them reasonably well but not enough to take that copper out of the bore. Copper plated bores are your friend if the bore's rough. All my match grade arsenal barrels in Garands had a lot of copper wash in them when they shot most accurate. No worse than 4 to 5 inches at 600 yards with a copper plated bore is something to rejoice with.
Besides, opening up a bore a few ten-thousandths typically makes them less accurate. Worse if it's not done uniformly. Fire lapping a bore makes it larger at the back end where the abrasive on the bullet removes the most metal.
If any barrel shoots bad after a dozen or more shots, I doubt it's copper fouling that cause the problem. If shots start stringing in one direction as the barrel warms up, that's a sure sign of the barrel not fit properly to the receiver. Too bad that virtually all commercial rifles do that, but they don't square up their receiver faces so their barrels fit hard at only one point around the barrel shoulder against the receiver.
Sometimes (more often than people realize), the human shooting the rifle changes his position and how the rifle's held against him after several shots are fired. That's one sure way to have bullets no longer strike the point of aim.
Instead, shoot it a few times to lay enough copper in the rough spots low points, then no more copper will get removed from subsequent bullets.
Having shot a number of rounds of match grade ammo in rough bores of commercial and arsenal barrels, they all did quite well after half a dozen or so shots were fired through them. Clean them reasonably well but not enough to take that copper out of the bore. Copper plated bores are your friend if the bore's rough. All my match grade arsenal barrels in Garands had a lot of copper wash in them when they shot most accurate. No worse than 4 to 5 inches at 600 yards with a copper plated bore is something to rejoice with.
Besides, opening up a bore a few ten-thousandths typically makes them less accurate. Worse if it's not done uniformly. Fire lapping a bore makes it larger at the back end where the abrasive on the bullet removes the most metal.
If any barrel shoots bad after a dozen or more shots, I doubt it's copper fouling that cause the problem. If shots start stringing in one direction as the barrel warms up, that's a sure sign of the barrel not fit properly to the receiver. Too bad that virtually all commercial rifles do that, but they don't square up their receiver faces so their barrels fit hard at only one point around the barrel shoulder against the receiver.
Sometimes (more often than people realize), the human shooting the rifle changes his position and how the rifle's held against him after several shots are fired. That's one sure way to have bullets no longer strike the point of aim.
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Howard Roark
Member
Sounds like all of the Douglas .223 barrels that I've ever had. They all had copper streaks left down the bore after cleaning and they all shot very, very well.
entropy
Member
Best way to do it.
highlander 5
Member
I've used both the system from Veral Smith and Midway with good results. Have a Ruger Bisley that had a restriction where the barrel was screwed into the frame and a very rough bore. Using Mr Smith's fire lap kit the restriction is gone and the bore is like glass.
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