I've been using Butch's bore shine, Rem-oil, and Hoppe's. I use Johnson's floor wax on the whole outside of the wood stock and all exposed metal.
i think it happens a lot. i'm guilty as well. thats why i use the outters. even after i clean with hoppes i can still gets lots of copper out with the expaning foamA barrel that's not REALLY clean can definitely hurt accuracy. The thing is that many of us, including me, have thought we were cleaning really well, but in fact weren't. I had some trouble a few years back with my sweet .280 that always hot 1 inch groups going nuts on me. At first, I thought it might be my scope, etc. because, after all, I always "cleaned" my rifle (I thought). After doing some reading and talking about the problem, I decided to try a new cleaning approach - that's when I discovered J-B Non-Embedding Compound and stared using the more aggressive Sweet's 7.62 and Barnes CR-10, and got my accuracy back.