I have a 7mm rem. mag with a 22", 1/11.5 twist Douglas barrel from the '60's. It will shoot heavier bullets OK, however bullets in the 140 gr. range are shooting lots better than their bigger brothers. As one would expect my velocities are off a bit also because of the shorter barrel. I shot lots of stuff through the barrel and spent several days at the range shooting and cleaning however the best I could do is 3216FPS with 65.0 IMR 4350 behind a Nosler BT .66 CTC 5 shot group. Sd was not there and I could not get this to repeat itself. So still looking Does anyone have software that could give me starting place for a faster powder like Varget or something around in that burn rate.