I have a factory barrel that copper fouls considerably. The throat is very long on this rifle and I don't need to lengthen it any more. I came across this article. Anybody on here ever done this?
I found an interesting article online at the Twin City Rod and Gun web site that provided a process for hand-lapping a barrel using three different grits of cleaning compound and tight patches. Fire-lapping involves shooting a bullet impregnated with lapping compound down the bore at a much reduced velocity and pressure. This has the effect of both polishing and tapering the bore for maximum accuracy, but it can also open and lengthen the throat. I found an article on the Los Angeles Silhouette Club web site written by Ken Mollohan that has a little different method for fire-lapping. Ken first ran a bore mop impregnated with J-B® Bore Cleaning Compound through the bore being careful not to get any compound in the chamber, then fired a low velocity, low pressure jacketed round through the bore. He repeated this process 5 or 6 times, then thoroughly cleaned the barrel. This process not only provided all the benefits of fire-lapping, but it prevented damage to the throat, and since the bullet itself was not impregnated with the lapping compound, the cartridge cases did not have to be thrown away.
I decided to try a combination of both methods on a new M1 Garand barrel. First I loaded 10 rounds of .30-06 with 5.0 grains of Red Dot behind a 150 grain FMJ boat tail .308 bullet and a large rifle magnum primer. I put an empty case in the chamber and closed the bolt to prevent compound from getting into the chamber, impregnated a bore mop with USP Bore Paste, then ran the mop back and forth through the entire length of the bore 20 times. This left a small amount of compound in the bore. I fired one low velocity round through the barrel, inserted the same empty case into the chamber that I had used before, then again ran the impregnated bore mop back and forth through the bore several times. This cleaned any powder residue and fouling from the bore and prepared it for a second shot. After performing this for 5 shots, I thoroughly cleaned the barrel using solvent and dry patches.
I threw away the first empty case I used and put a new empty case in the chamber and closed the bolt. I impregnated a clean bore mop with J-B® Bore Bright which has a finer grit and ran the mop back and forth through the entire length of the bore 20 times. I fired one low velocity round through the barrel, inserted the same empty case into the chamber, then again ran the impregnated bore mop back and forth through the bore several times. This again cleaned any powder residue and fouling from the bore and prepared it for a second shot. After performing this for 5 shots, I thoroughly cleaned the barrel using solvent and dry patches. The bore was mirror bright and smooth and was now ready for full pressure loads, and in theory the new throat was polished which should help to prevent excessive fouling.
The advantages of using this method are that the chamber throat is not excessively lengthened due to using rougher grit, and the cartridge cases can be reused for normal loads. As for the results, I fired maybe 60 rounds through the new barrel and it cleaned up with only three patches and I had no copper fouling. Now that's success!
I found an interesting article online at the Twin City Rod and Gun web site that provided a process for hand-lapping a barrel using three different grits of cleaning compound and tight patches. Fire-lapping involves shooting a bullet impregnated with lapping compound down the bore at a much reduced velocity and pressure. This has the effect of both polishing and tapering the bore for maximum accuracy, but it can also open and lengthen the throat. I found an article on the Los Angeles Silhouette Club web site written by Ken Mollohan that has a little different method for fire-lapping. Ken first ran a bore mop impregnated with J-B® Bore Cleaning Compound through the bore being careful not to get any compound in the chamber, then fired a low velocity, low pressure jacketed round through the bore. He repeated this process 5 or 6 times, then thoroughly cleaned the barrel. This process not only provided all the benefits of fire-lapping, but it prevented damage to the throat, and since the bullet itself was not impregnated with the lapping compound, the cartridge cases did not have to be thrown away.
I decided to try a combination of both methods on a new M1 Garand barrel. First I loaded 10 rounds of .30-06 with 5.0 grains of Red Dot behind a 150 grain FMJ boat tail .308 bullet and a large rifle magnum primer. I put an empty case in the chamber and closed the bolt to prevent compound from getting into the chamber, impregnated a bore mop with USP Bore Paste, then ran the mop back and forth through the entire length of the bore 20 times. This left a small amount of compound in the bore. I fired one low velocity round through the barrel, inserted the same empty case into the chamber that I had used before, then again ran the impregnated bore mop back and forth through the bore several times. This cleaned any powder residue and fouling from the bore and prepared it for a second shot. After performing this for 5 shots, I thoroughly cleaned the barrel using solvent and dry patches.
I threw away the first empty case I used and put a new empty case in the chamber and closed the bolt. I impregnated a clean bore mop with J-B® Bore Bright which has a finer grit and ran the mop back and forth through the entire length of the bore 20 times. I fired one low velocity round through the barrel, inserted the same empty case into the chamber, then again ran the impregnated bore mop back and forth through the bore several times. This again cleaned any powder residue and fouling from the bore and prepared it for a second shot. After performing this for 5 shots, I thoroughly cleaned the barrel using solvent and dry patches. The bore was mirror bright and smooth and was now ready for full pressure loads, and in theory the new throat was polished which should help to prevent excessive fouling.
The advantages of using this method are that the chamber throat is not excessively lengthened due to using rougher grit, and the cartridge cases can be reused for normal loads. As for the results, I fired maybe 60 rounds through the new barrel and it cleaned up with only three patches and I had no copper fouling. Now that's success!
