A local gun shop guy was telling me that the new powders with anti-copper fouling properties tend to burn dirty and build up a carbon ring in the leade of the barrel. He cited Hodgdon CFE 223, Alliant Reloder 16 & 23, and other new IMR powders as culprits. Have any of you heard of this issue or is it just gun counter babble?

Life Member NRA, RMEF, American Legion, MAGA. Not necessarily in that order.