Yeah as long as the twist is 1:48 or better. Powerbelt says they do even fairly well with the slow 1:66 twist but i never tried it for long range accuracy. Just 25 yards with a handful of shots.
Yes they do just fine...as long as you do not have a 1 in 66 twist barrel. I used a Lyman Great Plains 50 Cal with 90 grains loose 777 and 245 gr HP powerbelts to drop some deer a few years ago. I will try to figure out how to post a pic.