The regular CAS matches require rifles in pistol calibers, but there are sometimes side matches for big bore rifles like Sharps, Remington Rolling Block, etc. I guess if there was enough interest for late 19th century shooters like the Krag or the 1888 Commission Rifle, someone might have set up a separate course of fire for them. A Winchester 95 in .30-40 Krag might be fun, too.