I agree with David N. A lot of commercial barrels are rough enough that until enough jacket copper's laid down in them, they'll irregularly wipe off jacket material unbalancing bullets. Once those micropits are full of copper, bullets no longer leave a tiny part of their jackets behind.
I've shot matches with Winchester factory match rifle barrels and always went to the sighting in range to shoot a few shots to condition the bore before going to the range where the match was. Otherwise, the 2 sighting shots allowed before the first record shots were fired didn't foul the bore enough for best accuracy. They started out going towards 10 o'clock; apparantly unbalanced such that they jumped in that direction upon exit from the muzzle. 86 rounds later, the barrel still shot very well, but it got totally cleaned that night.
CC268, never put more than 100 rounds through a barrel before cleaning it with bore cleaner. I sometimes would dry brush it after 40 or 60 rounds. I've never used copper remover after Shooter's Choice. I have used Sweets 7.62 ammonia based copper cleaner and it's probably the best. But it's high level of ammonia burns my fingers and the fumes are not pleasant in my nose. I've also used a 50-50 mix of Hoppe's No. 9 and 28% ammonia which is way too toxic for my liking.
When Shooter's Choice first came out, they got sued by some errant rifle shooter who never cleaned his barrel too well over several thousand rounds. The barrel's throat was so full of crud that it still shot reasonably well. The strong cleaning of Shooter's Choice cleaned all that stuff out and left the very eroded, rough leade and origin of the rifling bare to scrape off and deform really good bullets. So proved the attorney for Shooter's Choice before they went to court. The errant rifle shooter decided it wasn't a good idea to pursue it further. As told to me by Boots (Barrett) Obermeyer, the barrel maker who made the barrel in question.
I've shot matches with Winchester factory match rifle barrels and always went to the sighting in range to shoot a few shots to condition the bore before going to the range where the match was. Otherwise, the 2 sighting shots allowed before the first record shots were fired didn't foul the bore enough for best accuracy. They started out going towards 10 o'clock; apparantly unbalanced such that they jumped in that direction upon exit from the muzzle. 86 rounds later, the barrel still shot very well, but it got totally cleaned that night.
CC268, never put more than 100 rounds through a barrel before cleaning it with bore cleaner. I sometimes would dry brush it after 40 or 60 rounds. I've never used copper remover after Shooter's Choice. I have used Sweets 7.62 ammonia based copper cleaner and it's probably the best. But it's high level of ammonia burns my fingers and the fumes are not pleasant in my nose. I've also used a 50-50 mix of Hoppe's No. 9 and 28% ammonia which is way too toxic for my liking.
When Shooter's Choice first came out, they got sued by some errant rifle shooter who never cleaned his barrel too well over several thousand rounds. The barrel's throat was so full of crud that it still shot reasonably well. The strong cleaning of Shooter's Choice cleaned all that stuff out and left the very eroded, rough leade and origin of the rifling bare to scrape off and deform really good bullets. So proved the attorney for Shooter's Choice before they went to court. The errant rifle shooter decided it wasn't a good idea to pursue it further. As told to me by Boots (Barrett) Obermeyer, the barrel maker who made the barrel in question.