Haven't tried the Hawk bullets yet but I've had good luck with the Buffalo Arms 200 gr. slugs with H4895. The best accuracy I got from a 1908 made '86 was the start charge in hornadys manual 35.1gr H4895. IMR 3031 has worked good for me too with bullets cast from Lyman .338320. Might want to give Hawk a call or email I've heard something about them being soft copper needing to be loaded a little lighter than normal gliding metal jackets.
Hope this helps.