Glock G19 Black G5 9mm Handgun Magazine - 15 Rounds. Glock's compact & subcompact 9mm magazines deliver the same rugged, combat-ready reliability and the same durable polymer-and-steel construction as their full-sized counterparts-all in a smaller package that's more practical for everyday carry. These standard capacity 15-round magazines are engineered for optimum fit and function in Glock 19. They feature reinforcing steel inserts, flush fitting Glock baseplate, and numbered witness holes for tracking capacity. Glock magazines come from the factory with relatively stiff springs to ensure reliability in the toughest of conditions.