CRS,
Well done!
Both my wife and I have used the 70-grain GMX on antelope from 1-8 twist .22-250s. Both rifles were special runs from Whittaker Guns in Kentucky a few years ago, a Ruger American and a Tikka T3x. I used the RAR on the biggest buck we'd seen locally in several years, and it worked fine at around 350 yards, ar a muzzle velocity of 3400 fps. That one got "caught" because the buck was angling away, and the recovered bullet weighed 70.5 grains, because there was some antelope meat under the curled-back petals. The buck went 20-25 yards.
Eileen used the Tikka last weekend to take a doe at 200 yards, and it crumpled at the shot, partly because the bullet broke one shoulder--but like most monolithics it didn't ruin much meat at all. That one exited. (She uses the same handload I'd worked up for the RAR, which for some reason gets around 100 fps less velocity in the Tikka, but the same very fine accuracy. Which is yet another example of why I don't obsess about finding the absolute top velocity in handloads anymore.)
