In a strong, rigid action, the 303 British is a ballistic twin to the 308 Winchester. The larger bore/groove theoretically should allow slightly higher velocities for a given powder charge, but that is a rather moot point. I, for one, would love to own a #1 Ruger in 303 British. The 303 has a long and colorful history, and has played a vital part in the development of Canada over the past 100+ years. Regards, Eagleye.