Basically the 5.45x39mm chambered version of the standard 7.62x39mm RPK. Several years ago some Bulgarian RPK-74 kits were imported into the U.S. The thought was that more kits were coming but only several hundred made it over. Even if you manage to find a kit, the problem is finding the receiver to build it on since NoDakSpud no longer makes one for the RPK-74. (GRH)