The MK-01 weapon system was designed by the Cuborg military's defense contractor, Cuborg Defense Industries (CDI), for close quarters fighting. The weapon uses assault rifle ammunition (7.62x39mm rounds) but its firing speed, weight, and size are modeled after a submachine gun style of weapon. The MK-01 uses a bullpup configuration to achieve greater accuracy and velocity. The MK-01 was greatly disliked by Cuborg soldiers, who preferred the AK-47, and the entire MK program was canceled. A huge stockpile of MK weapons are currently being sold to miscellaneous third-world nations.