Thank you Mister 303Guy. That helps substantiate what I thought I knew all along. I never examined recovered rifle bullets but I have a few thousands of pistol bullets from a sand berm. I never did see any signs of erosion on any bases but them again I did not specifically have that idea in mind either. All my thoughts were on the rifling grooves and mushroom performance.
Now I will pay special attention to any recovered paper patches to see if there is any sign of being burned other than smoke damage,