[garrisonjoe]

Lowest load in the data for a given component set is usually dirty.

Nobel 686 is a cooler primer. Yes, a Win 209 primer would help some with powder burn, but I'd also step up the powder to the 1250 FPS level and try again.

You have to remember that WSH is intended for a handicap (AKA higher velocity) loading. So it needs the pressure of that kind of load to burn the powder well.

good luck, garrisonjoe