A longer barrel, of 24" or more, is required on magnum cartridges, and it goes like this, 24" for standard length magnums, 26" for the Weatherby Magnums and Remington Ultra Magnums, and 28" barrel for the catridges, based on the .378 WBY Mag case and that includes the .378 WBY. Stick with that criteria, and they will obtain optimum performance. A shorter barrel, like 22", in a magnum chambering, is just a waste of money, the cartridge will never be able to obtain magnum performance.