Finally settled on a load for my 69 RMRs'. Using W748 25.5 grains with a CCI #41, LC brass. Oal 2.246
The above is giving me 2822 FPS , extreme spreads in the teens and single digit SD.
With my 20 in Krieger barreled upper, the average group size stays under .75 in for the last 10 5 shot groups at 100 yards. Some in the . 4 inch range but most in the .6 in range. I shoot off a concrete bench with a heavy bench rest style front rest and a bunny ear rear bar.
In my Rainier 18 inch SPR barrel ( Melanited ). It stays around 1 in. About the best this barrel has averaged.