I've used a virtual chemistry set over the years, but read the post about CLR and couldn't bring myself to put it in a rifle barrel. Might be fine, but....
A while back, a friend brought over his new bore scope which revealed that many rifles I thought were clean had both copper and carbon fouling remaining. Since I had cleaned my rifles faithfully, whether they had been fired once or 300 rounds at a match, this came as quite a surprise so I ordered a Lyman bore scope and half a dozen additional solvents from Brownell's and set out to determine the most effective ones based on fact, not supposition. The old standby's obviously were not doing the job. (The scope is still on sale @ Brownell's for $175).
The scope quickly reveals that a white patch is no guarantee that all copper has been removed. After cleaning w/conventional solvents (including occasionally with JB and Gold Medallion abrasives) and achieving the white patch. This was a factory 308 Win barrel which has been lapped, yet shows both carbon and copper fouling after old methods produced a "white patch". It shoots moa with occasional 3/4" but only with 3 bullets (of dozens tried).
This picture is another factory barrel (338 WM) which has not been lapped which shoots .210 gr. NP's in the .5's w/boring regularity and sometimes a bit better with NAB's & NBT's. Just goes to show you, some pretty rough bores shoot surprisingly well.
This barrel had been cleaned and put away after achieving the "white patch", using my old conventional cleaning procedure. Tool marks are quite visible and the large copper patch in left picture was a fairly large pit. Suspect this was a flaw in the barrel blank but cannot be sure as I was not original owner of this rifle.
After trying the new (to me) solvents I found Tactical Advantage (by the same folks who make Wipeout) to be the most effective at removing both carbon and copper. I found most of the other copper solvents to be less effective on powder fouling. I apply TA to an IOSSO brush and scrub bore ten or twelve strokes, allow to sit overnight, repeat if necessary. This removed the remaining copper and traces of carbon left after cleaning the old way.
"Even if you do patch it well afterward, what about the few drips that always find their way into the action and such?"
A good bore guide eliminates this problem, and I stand my rifles muzzle down to eliminate the possibility of any preservative draining into action while stored.
Regards,
hps