A fellow shooter told me about his .22/250, which had 750 rounds through it and had suddenly started firing patterns instead of groups. He took it to a gunsmith, who accused him of Bore Abuse and said he needed a new barrel. The shooter described his cleaning technique, which involved J-B Non-Imbedding Bore Cleaning Compound and a very popular powder solvent, and said that he thought he was doing an adequate job of getting the copper out of the bore, and that he was not guilty of bore abuse.
I told him that “Sudden Accuracy Death Syndrome” is common, and afflicts thousands of innocent rifles which, when new, shoot like a house on fire and then very shortly will not group worth a tub of old hog s**t. The reason is copper buildup in the bore. It’s almost impossible to burn out a barrel in 750 rounds, and cleaning rod abuse happens very gradually. But copper buildup?
J-B is what I use to remove copper too, and it always works, but you have to use it correctly. That .22-250 shooter was not. He was putting it on a brush rather than on a tight patch, and using far too few strokes. His powder solvent was less effective than Shooter’s Choice, which is what I have used for years. It smells awful, but it works.
In order to make J-B work, you must also buy a can of Kroil (Cabela’s and Brownells carry it), a very thin, pungent, penetrating oil. When used in combination with J-B it develops awesome copper-scrubbing powers. Wet the bore with Kroil. Then take a blob of J-B, roughly the size of a good phlegm globber, and work it into a patch that you have wrapped around an old bronze brush. This patch should fit tightly in the bore. I will say that again. This patch should fit tightly in the bore.
Give the patch 30 trips back and forth. There’s no reason for this particular number. You can make it 20, or 40, or 37. Some bores will clean up with one patch. Most will not, and this is where people go wrong with J-B, whose essential ingredient is elbow grease, which you have to supply. Most of my rifles take three J-B patches with a Kroil patch in between.
The patches will come out black, or dark gray, with black streaks from the lands. You don’t clean until this stops, because it never will. All you want is the copper gone, and to see if it is, get all the J-B out with Shooter’s Choice and leave the bore wet for at least 2 hours. At the end of this time run another S-C patch through and see it there’s green or blue on it. If there is, you can do one of two things: Keep up the S-C treatment, which usually takes a while, or go back to the J-B, which is much quicker.
I also advised the .22-250 shooter that if he really wanted to do something useful in the way of barrel cleaning, he should invest in a Hawkeye Bore Scope, which costs about the same as a good scope sight. That way, you actually know what the hell is going on in your bore instead of guessing.
Do not be afraid to scrub a bore. If you use a good rod and keep it centered, there’s no way you can hurt a barrel with J-B. Copper is fine when it’s part of a bullet, but when it becomes part of your bore, it’s a rifle-wrecker.