I'm working up 25 and 338 caliber x bullet loads for plains game next year and got myself in a tizzy cause of all the fouling I saw at the muzzle. As it turns out it's not an accumulation of copper at all. Just copper color painted on the steel...carbon steel for the 25-06 and stainless steel for the 338-06AI. These two barrels don't seem to foul any more, or less than with guilding metal clad bullets.

Just for giggles, I'm gonna plate some with Midway Moly to see how well they shoot. I don't go for 14 months, so I've got plenty of time to play around.