Re: Slow Powder New Brass= Black Crap??
I had the same results last weekend when finishing barrel break in for a friends 257 WM. He was using the lightest charge weight listed from hodgon for H4350 w/ the 115g vld. I noticed the black crap as well and figured they were light laods. The next time out, I cronographed a few and noticed they were only doing 3000fps which is a bit low on the velocity scale.
Shot some upper end loads w/H4350 and 100g NBT's this morning and the soot went away.