I have 2 Rock barrels, one on a 6.5x284 and one on a .308, both built by GAP. I broke them in per GAP's instructions. I cleaned after every shot until they quit copper and powder fouling.
On the 6.5x284, the barrel fouled horribly, with no noticable difference until the 8th shot, after which it required around 20 passes with a brush with SC. I followed that with 50BMG and it came out totally clean. It was like a veil was lifted after that 8th shot, and it continues to clean down to bare metal very easily.
The .308 was slightly different. After each shot it cleaned up easier and easier, up to the 6th shot where it was broken in as far as I was concerned. It went from the first round down the barrel requiring 100 passes with a brush with SC to get the powder fouling out and 3-4 times with 50BMG to get the copper out to requiring only 20passes with the brush and SC for powder fouling and 1 time with 50BMG. It continues to clean up very easily as well.
These are the only 2 custom rifles
I own, but I have had great luck with Rock barrels and GAP as well. Both rifles will consistently shoot 1/2 min @ 1000yds. in a no-wind condition, for 3-5 shots.
Hope this is what you were looking for.