Semisane - interesting test you made, and obviously, the slower powder was better. I would expect due to the 30" rate
of twist, a shorter, lighter weight bullet might have done better, and indeed, perhaps a slower powder as well, as in 1FG
could be tried, even with that heavy-for-twist bullet. I would think for a 30" twist, a 270gr. to 300gr. bullet might be much
better. Of course, loading the shorter bullet straight, might be a problem.