I reload for my Marlin 338 in 30/30. I found that 35gr of IMR3031 behind a 150gr Win RN was the most accurate load and give me around 2500fps (I don't have my load book right now but I think thats about right). Definately work up any load from below listed max till you find the best accuracy within the limits.

If I had it to do over again, I would have probably went with the 35 Rem instead of the 30/30. It has similar speed and balistics but with a 200gr bullet. The 444 or 450 would be nice also.