Re: More fouling than in my underwear
You had a bad experience with them. My 416 WBY put's the 400gr XLC's under .8 MOA and my sons 308 put's the 150 XLC under about .6 MOA. The 165 and 180 XLC's did not shoot well, nor did the 150 with anything I tried other than a stiff load of RL15. The 416 WBY works well with the 400gr at 2650 fps with 115gr RL22.
Alternate cleaning with JB Bore Paste (30-40 strokes or what have you) then Sweets 762, JB, Sweets etc. Usually the JB will take down the copper fouling real quickly by itself but if you feel better and think it's any quicker add in some Sweets to the process. My 300 Ultra barrel cleans up pretty darn easy now after about 500 rounds and multiple JB polishings.
Do yourself a favour and make sure you clean the chamber and bore well after using JB. John M. turned me onto using alcohol to get it spotless. Then I use a bit of solvent, dry patch, then oil up good followed by two dry patches.