I've been working with Retumbo in my .264 Win Mag. Using a 129gr Hornady Interbond, my load of 68gr of Retumbo (0.5 over max FYI), gave me an average velocity of 3172 with the 24" barrel on my M77 MkII. Extreme spread was 59.95 fps, which Im finding normal with Retumbo, super sensitive. I have no pressure signs what so ever. So I'm going to keep ringing it out to see what I can get out of it. I think I'm going to switch to RL22 and see how that works out.