6mm XC Ammo
6mm XC (also known as 6XC) is a "wildcat" rifle cartridge, similar to the 6x47mm Swiss Match.
The 6mm XC was initially developed specifically for NRA High Power match shooting by 11-time NRA High Power National Champion David Tubb. It is touted as being one of the most accurate long-range 6 mm rounds in the world that is designed for repeating rifles.
Originally, the case for this wildcat had to be formed from .250 Savage brass, but it is now commercially available.