Wipe-Out also works well, but in general takes longer than the Montana X-Treme products, especially Copper Killer.
I've often encountered rifles that shoot best when fouled in various degrees. The most memorable was a .300 H&H with a custom cut-rifled barrel that had to be fired 12-15 times after a bare-metal cleaning before it settled down, but it would then shoot great for 80-100 rounds without cleaning. In fact, it drove me nuts for a while, because my normal "break-in" routine (if you can call it that) with new barrels is to clean the bore after every range session for a while. Was working up loads for this rifle, shooting a few handloads at a time, and it was NOT shooting well. Finally one day I decided to try a BUNCH of different loads, and after about a dozen shots the rifle started shooting really well, with just about any load. That's when the light went on....
If rifles require very frequent cleaning to shoot well, I treat them with Dyna Bore Coat.
All of this is why I keep a log of the shots fired from all of my rifles, along with cleaning intervals.
