Here are the load I use, 444 Marlin, 300 gr. Cast (MBW), H 4198, 39.0 gr., WLR, 2.570. I shoot this load in my Encore 444 Marlin. I also use it in my Marlin GG. I worked up to it, and that is where I stopped when I found the accuracy I was after. You can start at 38.0 gr. and work your way up. Max load is at 42.0 gr.