Tried the 4350 and with my rifle doesn’t seem to like it as much as the RL 15. I have read several blogs on the RL 17 being a better performer for the target shooter from long range. I have at most a 385 yard shot from my box but I am insanely picky about the accuracy of my shots.
The military uses ball powder for contract 223 and 308, but after two years of playing with both and shooting many groups with full load ladders, I consistently find stick powders like 3031 to be more consistent and accurate than ball powders. I load ball powder for all my tactical practice and plinking rounds, but for accuracy (less than 0.4 MOA average, best groups through the same hole at 0.1 MOA) I have been really happy with 3031.
My apologies for misreading your question. RL15 is a ball powder but it seems RL17 is a extruded powder. I’ve never used it. Give us a range report when you get some loaded and fired. :)
What rifle are you launching from?