I first started using kroil when I was on the Molyed Bullet kick. I did alot more shooting then and used moly in my varmit rifles and small pores. It helped clean the bbl with out removing the moly "seasoning" from the bbl and I found that I could get away with cleaning after 50 or so rounds before my accuracy suffered. Kriol was simple, wet a patch, let it soak and then knock it out with acouple of dry patches. It worked great.
I now use kroil as a finish to my cleaning routiene. I clean with a copper/powder solvent first then I wet the bore with kroil let it sit for 10 miniutes or so then dry with a clean tight patch.
It will not hurt you barrel and does help in future cleaning.
As a side note, make sure you don't get any into your trigger group or bolt and clean it up out of the action as it will gum up. It is not a mechanical lubercant, it is meant to break free rusty parts and as a bore cleaner. The petroleum distillates will evaporate and leave behind an awful mess. (I found this out the hard way and cleanup was a real pain.)
Dan