Mossberg's 590M Mag-Fed shotgun features innovation at its core with the detachable magazine's integral stabilizing ribs which engage the magazine directly to notches engineered into the receiver for a positive lockup. The all-steel magazine release button and housing are optimally positioned in front of the trigger guard and will not interfere with cycling of the action. 590M compatible magazines are available in 5, 10, 15, 20-round capacities for added versatility in selecting capacity or specific load.