I been moly coating bullets for a few years now and just cleaned the 257 weath mag.The rifle loves the 115grn Bergers or 100grn SMK's and seen nothing but my moly coated bullets from day one other than a box of factory to break the barrel in.I clean this baby every 15 to 30 shots no matter what.Plugged the barrel and filled it up with KROIL and a few swipes with a brush and patch has it like brand new.No copper fouling and very little carbon.Might get to push a few rounds at 400 yards this weekend if its nice out.Barrels are funny and seems like this one does its best at number 3 shot to 20 for great accuracy.When I say great,i mean 1.5" or less at 400 yards and all other shots before or after 3 to 20 still smokes a three inch dot.I just think its best to keep it clean instead of letting fouling build up.
Moly fouling seems to go away very fast when cleaning with Kroil oil and a super smooth barrel helps more than anything.I will try to figure out pics on here and will post a few if I get to shoot at 400 yards.My range is 220 but that's no fun anymore.