Looking for some insight from the more experienced amongst us. I'm new to loading so my supplies are fairly limited. I made loads for my 30-06 and 7mm rem mag, using the same powder (imr 4350) but after firing, I noted the inside of the 7mm brass is black like diesel exhaust but the 30-06 isn't any dirtier than I'd expect. Both used Winchester primers. What's the deal?