I very seldom clean my high volume rifle barrels unless there's a reason, which is rare unless it's an overbore chambering that's pushed hard. I've got a couple 6.5CMs that I shoot in PRS matches that have had their muzzle brakes cleaned more frequently than their barrels. These rifles have been cleaned every 600-800 rounds. Accuracy returns after the barrels are fouled.
i've also generally stopped scrubbing hunting rifle barrels like I used to. Unless there's a loss in accuracy, I'm putting a rifle up for long term or some other incidental reason, I don't clean the bores. Store riles vertically with bolts open or bolts out and shoot'em dirty.
