Clip

Ammo clips are an ammo pick-up containing 10 bullets for the pistol or chaingun (20 at the I'm Too Young To Die and Nightmare! skill levels). The clips dropped by slain zombie troopers contain only 5 bullets (10 at the I'm Too Young To Die and Nightmare! skill levels).

Each bullet does between 5 and 15 hit points of damage (determined using Doom's pseudorandom number generator). Note that this differs from the bullets fired by troopers and chaingunners, which inflict 3-15 points each.

Although referred to in the game as clips, the objects depicted are clearly magazines; that is to say, they contain bullets rather than merely hold them in place. 

Appearance statistics
The IWADs contain the following numbers of ammo clips (excluding those of dead Troopers):