Left 4 Dead 2/Weapons

Melee weapons
The melee weapon will take up your pistol slot. While only working at short range, they inflict more damage and can generally take care of the infected as they are close up.

If you are knocked down, you will use a single pistol instead of swinging your melee weapon.

Baseball Bat
The bat is only available to players that pre-purchased the game, or players in the same server as a pre-purchaser. It has average damage and swing speed.

Chainsaw
The chainsaw runs on gasoline and can't be refueled. It will only use gas when you attack with it. It is, however, arguably the most powerful melee weapon in the game, dealing 200 damage per half-second and able to kill a Witch in 2 seconds on Normal difficulty.

Cricket Bat
This bat deals 500 damage per swing and has a relatively long reach, but swings rather slowly.

Electric Guitar
The electric guitar is a large, two handed melee weapon. It takes up a significant portion of your screen, and can behead enemies.

Fire Axe
The fire axe is the typical red-headed blade on a stick. Like the electric guitar, it is two handed and can be used to behead enemies. 400 damage.

Frying pan
The frying pan is a one handed blunt object. It is fast, but cannot behead enemies. It can be found relatively commonly.

Katana
The katana deals 500 damage and has a fast swing, but has a slightly longer cooldown time.

Machete
While only dealing 250 damage, the machete makes up for it with good speed and cooldown. The low damage doesn't make a huge difference to begin with, as common infected never have more than 100 health.

Nightstick
Also known as a Tonfa, this weapon swings extremely fast but deals less-than-average damage. Riot Infected will sometimes drop these upon death.

Crowbar
Deals 500 damage, and swerves the player's screen a bit upon swings.

Pistol
The regular pistol, with a new skin, from the original Left 4 Dead. (This game's pistol is a P220, and a Glock when dual-wielding). Like in the previous game, the pistol can be dual-wielded. If you trade your two pistols for a melee weapon or a magnum, you will only be able to trade back for a single pistol.
 * Magazine capacity: 15

When dual wielding you will be able to fire 30 rounds instead of 15.

Magnum
The Desert Eagle magnum has a smaller magazine capacity, but deals more damage—80 points to the P220's 36. Like the regular pistol, the magnum also has unlimited ammo. Its speed is usually a factor when deciding between two regular pistols or a melee weapon.
 * Magazine capacity: 8

Chrome Shotgun
More accurate than the pump shotgun, but inflicts less damage per shot.

Combat Shotgun
More accurate than the tactical shotgun, but inflicts less damage per shot.

AK-47

 * Magazine capacity: 40
 * Total ammo capacity: 400 (360 + 40)

M4A1

 * Magazine capacity: 50
 * Total ammo capacity: 410 (360 + 50)

Combat Rifle

 * Magazine capacity: 60
 * Total ammo capacity: 420 (360 + 60)

Fires in three-shot bursts.

Silenced SMG
Inflicts more damage than the normal Submachine gun, but is less accurate.

Hunting rifle

 * Magazine capacity: 15
 * Total ammo capacity: 150 (135 + 15)

Sniper rifle

 * Magazine capacity: 30
 * Total ammo capacity: 180 (150 + 30)

More accurate than the hunting rifle.

Grenade launcher

 * Magazine capacity: 1
 * Total ammo capacity: 31 (30 + 1)

This weapon appears in limited quantity in the campaign, usually in a side room off the main path. It cannot be refilled at ammo piles, but has enough ammo to last through a given level.

It can be found in stadium in The Concert, the final area of the Dark Carnival campaign.

Pipe bomb
The pipe bomb is a throwable weapon. It emits a loud beeping sound to attract common infected to the grenade before exploding.

Molotov
The molotov is a glass bottle full of flammable liquid. It shatters on impact and ignites a large area for about 15 seconds.

Boomer bile
Boomer bile is a canister containing boomer bile. When thrown, it shatters and causes common infected to either approach the bile cloud or targets hit with the bile. The common infected will proceed to attack the bile in question.

Medpack
The Medpack heals you or another survivor.

Defibrillator
The defibrillator is used to revive survivors who have died. If a survivor revives within a closet, they cannot be revived using the defibrillator (their corpse will have disappeared).

Pills
The pills are a quick way to refill a portion of your health. They are best used when you are close to death (1-20 health) or bleeding. If you are limping, using pills can increase your speed temporarily.

Press alternate fire to give the pills to another survivor.

Adrenaline
Adrenaline restores 20 health and puts you into a heightened state. You will move and attack more quickly for about 30 seconds, but your vision will be distorted.

Lasers
A laser is an accessory that is added to a primary weapon to improve its accuracy. It provides a laser dot when attached. Lasers cannot be attached to pistols, items, or melee weapons.

You can find lasers in white boxes, similar to the fragmentation or incendiary ammo boxes.

Fragmentation rounds
Fragmentation rounds explode on impact.

You can find fragmentation rounds within tan ammo boxes.

Incendiary rounds
Incendiary rounds cause targets to catch fire.

You can find Incendiary rounds within orange ammo boxes.