The P220 pistol's damage fall off is it loses 25% damage per 500 Hammer units. However, it is still limited to a magazine capacity of 15 rounds.
The Pistol is one of the only weapons that has infinite ammunition. It is one of the weapons they can use when knocked down, although with a slower rate of fire, greatly decreased accuracy and slower reload time. The P220 Pistol is the backup weapon of the Survivors in Left 4 Dead 2, replacing the M1911 Pistol from Left 4 Dead.
Infinite ' Gonna go all akimbo and shit!' ― Coach ' Going with the double pistol, heck yeah.' ― Ellis