RL-17 worked good for me when I had my 10-T 6.5cm. 42.0 gr @2795 fps. Tried a little higher but started getting case swipes. Grouping was sub MOA. Was looking for RL-16 but finally found 1 lb of H4350 to try. Didn't group well with more powder than RL-17. Ended up selling the rifle and getting a 338LM.