how does the magazine on a p90 work
FN P90 The P90 uses a unique horizontally mounted feeding system—patented in the United States—that contributes to the weapon's compact profile and unusual appearance.[12] U.S. Patent 4,905,394 ("Top mounted longitudinal magazine") was awarded in 1990, naming René Predazzer as the sole inventor.[31] The detachable box magazine is mounted parallel to the P90's barrel, fitting flush with the top of the weapon's frame, and it contains 50 rounds of ammunition which lie in two rows facing left, offset 90° from the bore axis.[17] As the cartridges are pushed back by spring pressure and arrive at the rear end of the magazine, they are fed as a single row into a spiral feed ramp and rotated 90 degrees, aligning them with the chamber.[17] The magazine body is composed of polymer, and it is semi-transparent to allow the shooter to see the amount of ammunition remaining at any time.[17]