The Glock has moderate accuracy, moderate stopping power, but is the slowest firing sidearm in the game. Only use this gun if the following happens;
1) Your M16 is out of ammo and you need a gun.
2) Your M16 can't shoot over a small wall, so you need a gun that can shoot over it.
3) You are on a hill, and you don't want to waste your m16's ammo spraying, so you need a gun that has unlimited ammo.
4) If you don't really need to get kills with your guard while you have your shield up.