They'll all work.
270 is best suited for velocity, and monos NEED velocity. Watch your twist rate.
By the way a 270 in the hands of a good hand loader can do some incredible things like slinging a 150 grain bullet approaching 3100 ft per second with a slow burning powder. The only downside is 277 doesn't have the highest selection of bullets, and the factory twist may not stabilize long boys.
270 is best suited for velocity, and monos NEED velocity. Watch your twist rate.
By the way a 270 in the hands of a good hand loader can do some incredible things like slinging a 150 grain bullet approaching 3100 ft per second with a slow burning powder. The only downside is 277 doesn't have the highest selection of bullets, and the factory twist may not stabilize long boys.