I used this stuff on 2 CMP M-1 Garands, and it worked great. One barrel took about 8 or 9 applications, the other around 13 or 14. Yeah, that's a lot of cleaning, but each time up till the last the foam came out discolored, so it was working. The first few treatments turned blue, indicating copper. I can't imagine how long it would have taken with normal bore cleaner.
I did these cleanings with the gas system removed, since I had the rifles torn down for their initial cleaning (by me). I'm not sure if there would be any problems if the foam got into the gas tube on an AR - it would certainly clean the small portion of the tube it came in contact with, but since you couldn't clean it out without disassembling, I dunno.
Opinions?
BTW - even after the 20+ applications above, I'd estimate I still have almost a half can left.