Hey, I'm glad to read your post because I've never fired anything over 50 grains .I was told that a 14" twist will not stabilize anything over 55 grains.
I have a Weatherby and can honestly tell you that whenever I see it compared to other new cartridges they use mild figures to make a point . Lately I've been using 165 trainers and have chronographed them at 3,450 fps with no pressure signs (extractor marks, cratered primers , stiff bolt etc.)...
I bought a 1917 Enfield. It shoots a .308 Norma Mag. necked down to .257 cal. I was shooting 100gr. bullets at 3,740 fps but backed off --- didn't want go burn my barrel out . It's pretty flat shooting. I'm using RL22 and 7828 . I've gotta try some of the new powders out .