Those pistol 300gr. should work well in a .452" groove diameter bl. Nice to have a choice, Speer 300gr. and 260gr. as well, Sierra and Hornady.
I shot a bear in the face with a Speer 260gr..451" at about 5 yards with a .45 Colt Trapper. The bullet was loaded to 1,960 fps. Killed him, but didn't exit.