Pistol (Left 4 Dead 2)

The SIG Sauer P220 Pistol is the backup weapon of the Survivors in Left 4 Dead 2. It is also the only weapon they can use when knocked down, although with a slower rate of fire and greatly decreased accuracy. Besides the minigun, the pistol(s) is the only weapon that has infinite ammunition. However, they are still limited to a magazine capacity of 15 rounds.

Even though they are meant as emergency weapons, the pistols make great secondaries, or even primaries for Hunting Rifle, Sniper Rifle, Grenade Launcher and any shotgun users. They pack a punch slightly greater than that of the assault rifle, and possess above average accuracy. Pistols will usually spawn on the first level of each campaign. This occurs most frequently on easy and normal. However, on advanced and expert, they are often not available during the first level.

In Left 4 Dead 2 Demo, upon picking up a melee weapon, Survivors drop their pistol (if they are dual wielding, they will drop both pistols). However, when they are incapacitated, they still pull out a pistol, and once revived, the pistol is no longer part of their inventory and the melee weapon is still in the pistol slot. This is most likely a bug, since it would be illogical for Survivors to drop their only usable weapon when down. Or another possibility would be that the Survivor will keep an emergency pistol, but still upon picking up a melee weapon, it still shows a pistol-drop animation. The most likely cause is the designer's intent to keep the "downed" gameplay mechanic intact, even if the survivor has picked up a melee weapon.

Dual-Wielding
If a second pistol is found, they can be dual-wielded. Once you equip another Pistol you will have a Glock 17. Second pistols are placed periodically by the Director and can also be picked up if dropped by a teammate who has picked up a magnum, melee weapon, or has died. This allows for twice the ammo capacity, as well as the rate of fire being increased from 300 RPM to 600 RPM. The downside of having two pistols is that it takes slightly longer to reload, but the extra damage and rounds are worth it. When dual-wielded, the pistol in the left hand will not have a light.

Trivia

 * Currently, the P220 doesn't have a walking animation; it stays completely still on your screen.