Recently, I read somewhere, that the copper fouling in a Stainless Steel barrel made the patches GRAY, while the fouling in a non-stainless barrel was BLUE.
I even repeated this, and I'm sorry I did. Because, IIRC I had BLUE on the patches when I cleaned my One and Only SS barrel rifle.
I won't be able to check it until I shoot that rifle again enough to copper foul it.
So, I'm asking if the above is a True Fact.
Smitty of the North