The G19 is a mid-size pistol, shooting the 9x19mm pistol cartridge (9mm Parabellum), a standard military round that's easy to find ammo for anywhere. The GLOCK 19 is a short-recoil operated, striker-fire semi-automatic pistol. The Safe-Action trigger system makes shooting in stressed situations infallible. The main frame of the GLOCK pistol is constructed of high-strength polymer that is resistant to shock, caustic liquids, and temperature extremes. The model G19 comes with two standard 15-round magazines, or two 10-round magazines that comply with various city or state restrictions on magazine capacity.