I'd be trying H4831sc or RL22
the fastest load in a long barreled rifle will be the fastest in a short tube as well, so slow burning powders will yield the highest speeds on average
if you want to tame muzzle blast, try a powder like Varget or RL15, should still perform decent
maybe BC Bigbore will chime in, he's had good success with the 140 gr. Accubond in his 270 Win