Got shooting 270wsm with badly fouled and pitted barrel. I tried Winchester Staball 6.5 no data on it but I see it’s a slower burn rate than H&Imr 4350. I shot 57 grains behind a 130 grain Berger classic hunter on top of a Fed 215 match primer. Nice 1/2” group but very sooty cases all the way to the base. Any suggestions? It’s the first time I’ve ever pulled a load out of my butt so to speak! I assume the soot is from not enough powder to properly seal chamber with the brass.