My WSM has a 26" tube, and keeps 178gr. AMAX's supersonic to just about 1500 yards@ DA of about 6-8000 ft. It really depends on which bullet you want to run and what powder you have behind that bullet. If going with a short barrel, like say a 20", you might look into 155gr Scenars, with a Varget load. IMHO, going with anything under 20 to 22" is going to be a no-go because of excessive muzzle blast.