I'm currently using RL-17 and 270 gr Barnes 3X as my hunting load in my FN .375 Ruger with its 21" McGowan barrel. With 81 grs, velocity is +/- 2700 fps. With 270 gr Hornady IL's and the same charge, velocity is +/- 2750 fps. Accuaracy is 1-1.5" at 100 meters.
Edited to add:
Below is a quote I made on a thread sometime in the past that explains how I arrived at my loads. Apparently hornady's recent manual lists 81/270 gr as been maximum.
I'm working up to that in my Howa / 375 Ruger, but still well under 81 gr. using the 270 Hornady with really good results.





















































