I got the best accuracy in the guide gun and full length comboy limited with 405 gr sp bullets by Remington.
Of the 300 gr bullets, Federal seemed to be the best. Hollowpoints vs softpoints I'd rather have the old slow .45-70 stay together than fragment as it does its work.
Strictly anecdotal I didn't put any of the loads through a chrono, just seems like the heavier bullets got me smaller groups.
And welcome to THR!