ive been doing alot of testing for 2 different 270 wsm's. Everyone talks about RL 19 and 140 accubonds. For me it didnt shoot well in either. I have found that H4831SC with 130 Barnes TTSX to shoot best. Tried 4350, RL19, RL22, Retumbo, H1000, and 7828
I shoot 140 gr Sierra gamekings with 65gr H4831sc. Win. brass and Fed 210 primers. Velocity is at 3150 fps. Shoots .5 groups at 100 yrds and if I do my part inch groups at 500 yrds. No signs of pressure and my rifle loves the Sierra gamekings.
According to the Hodgdon web site 71.0 grains of Retumbo is listed as a max load, with a 140 grains bullets, and this gave 3165 ft/sec. velocity. I have worked up to this in my Winchester Model 70 and it has produced good accuracy and over 3100 ft/sec velocity.
I used Remington brass with WLRM primers and 140 grains Accubonds to work up the load.