The 12.7×55mm cartridge is used in some Russian firearms such as the VKS bullpup sniper rifle, the ShAK-12 bullpup battle rifle and the RSh-12 revolver.
The cartridge can carry a projectile weighing between from 108 grains and 1173 grains and is predominantly used to fire heavy subsonic loads.
The high penetration VKS round can penetrate up to 16 mm (0.63 in) of steel at 200 metres (220 yd) or body armor up to GOST 5A or NIJ III at 100 metres (110 yd).
The accuracy of this cartridge when loaded with precision VKS bullets is claimed to be one MOA at 100 metres (110 yd) up to the effective range limit of 690 metres (750 yd).
Despite being chambered in the same cartridge, the ShAK-12 (and RSh-12) would not be able to feed or chamber rounds designed for the VKS due to significant length differences in the bullet component of the cartridge and thus requires its own, shorter, loads.