Loaded several different loads to take to the range today.

Loaded some 180gr. Game Kings with RL 19 and Fed 210M primers. When fired, the case was covered with black soot. The bolt face too.

All the RL 19 loads did this. The other loads, using other powders did not.

Never had this happen before..sakofan..

.300 WM
180gr. Game Kings
Fed 210 primers
RL 19, 75gr.
Win./Fed. brass

It sounds like a ignition problem. Are your primers fully seated? Is the neck tight on your bullet? Is your striker gummed up or the spring weak?
Have you tried this load before?
I don`t think it sounds like the charge is too light but, soot on cases often comes with low pressure not expanding the case and sealing the chamber from gases.

Joe, I shot H4350, RL22, and the RL19.

The RL19 was the only load to do this on.

Iam about 1gr. under max load. 75gr. using a 180gr. GK.

The groups were surprisingly pretty good!!

The bolt face and lugs were sooty as well.

I thought it sounded like an ignition problem too.
..sakofan..

I use Rel-19 in my 6.5x55 and find it clean burning. However, I don't know about in other rifles than my own. Best wishes.

Cal - Montreal