These proprietary 10 and 5 round detachable magazines are for the AA9130 Archangel OPFORA(R) Series Precision Rifle Stock - suitable for most Mosin-Nagant rifles, both hex and round receiver, the Soviet M-38/M-44/ Chinese T-53 carbines, and Finnish M-39 rifles and carbines. The magazine body is molded from a proprietary carbon-fiber filled black polymer, and utilizes a proprietary feeding system. The magazine has a molded polymer follower for ease of feeding, and a heat-treated Chrome-silicon wire spring ensuring reliable feeding and function. Mfg: Pro Mag