Originally Posted by JeffVN
+1 on looking for a carbon ring. Regular cleaning cannot remove it. One way to tell (assuming you do not have a bore scope) is to pay close attention to when you run a patch (or brush) down your barrel. There will be resistance as you pass the ring, then much smoother progress down the bore after you get past it. I developed one in a .308 and a 7WSM. After doing so, regular loads were showing up with overpressure.
Here are a few articles about the carbon ring and its removal.
Carbon ring ?
Jeff, very interesting articles on the carbon removal methods. The GM top engine cleaner is incredible. I have been using it for years, and it really does work.
Another thing that works great is automatic transmission fluid. It works best when left in over nite. ATF fluid is very high in detergents, that attack carbon.
I have found that when using a lot of RL22' RL19, you have to keep an eye on the carbon. It builds up quick too. You get that roller coaster feel when you attempt to clean, and it is usually tighter at the breech end, then it smoothes out. Great thread!