I use 3.4gn GM3 shotgun powder with a 158gn SWC for gallery rifle stuff. It shoots within an inch at 25yds but we had a play at 163yds last week while we were out zeroing the 222 and 223. It was comical to watch the big lumps of lead going in like mortar shells. 15.4gn of H110 with a 158gn JSP was a diffrent matter though. Very useful out to 200yards. (the targets were set at 163yds cos the inconsiderate farmer hadn't cut his bean plants down to let us see the targets any further.

Bullseye is a very fast powder designed for hot loads in revolvers and pistols. The pressure peaks too quickly to be very good in long barrels. 8gn loads and upwards can destroy an underlever but work fine in a 4" revolver.