I considering a short magnum for a 1000m target rifle, perhaps in a Rem. short action 7mm or 30 cal. From what I've read so far the velocities tested by the manufacturers are hard to repeat in sporting rifles, especially in barrels 24 inches and under. I' m not sure how well they work with longer bullets.
As far as target shooting goes, these short magnums' resemblance to the famous BR line of cartridges is hard to ignore.