Generally speaking, the fastest powder in a longer barrel is also going to be the fastest powder in a shorter barrel. Mine likes IMR4451 for 130MK, and h4895 for 130 absolute hammer (Different beast altogether, tends to require much faster powder than same weight traditional lead core, or even traditional monos). I wont list loads, as mine is Ackley improved. In short, just select from powders listed in the manuals and their relative top speeds. You'll be slower, but it should be proportional. Seems like the h4350 burn rate range will be the happy spot for the 150Gr bullets. In the current climate, I'd say whatever you have on the shelf, or whatever you can find will work just great.