That's one vote for H335 ( YAY!!! I HAZ IT!) ..... and two for Varget.
FWIW, I am not yet set up for casting Boolits..... am planning on launching .311 150 SGK's out of my 91/30.
From what I've read, I am looking for a med-slow burn rate like 4064, H414, W760 ..... I would of thought that with that 28" barrel, even slower powders would work better..... H4831 or the 4350's ......
TheGolden Rule of Tool Use: "If you don't know what you are doing, DON'T."