MSS-2346 is a Japanese-made semi-automatic rifle developed in the late 1950s by the Howa Machinery Company as a part of the Ninigi weapons series. It is a gas-operated, air-cooled, magazine-fed rifle with a rotating bolt firing action, designed to fire the 7.62x51 mm NATO round. The MSS-2346 is a variant of the MSS-2345, originally designed as an infantry rifle; however, the MSS-2346 version was adapted for use by the Japanese Air Self-Defense Force as a light anti-aircraft weapon. The rifle is fitted with a ventilated handguard and barrel shroud, as well as a folding rear sight and adjustable bayonet lug.