I remember a review of a cheap Remington rifle (770? 783? one of those) by Dave Petzal. He said the bore looked like a coal mine, but the rifle shot lights out. Makes me afraid to look in the bores of my rifles.
On the other hand, I have a Tikka Model 558 in 243 which has always shot wonderfully well. All of a sudden, it stopped doing so. I borrowed a friend's Hawkeye bore scope, and took a look at the throat. It looks fine. I was sure the throat of a 25 year old 243 was worn out. It's not. The mystery deepens.
carbon fouling.
