Grenade Launcher

"I tell ya, it's gonna be rainin' zombie pieces."

- Coach

"Time to make some zombie soup!"

- Nick

The Grenade Launcher is a primary weapon that made its debut in Left 4 Dead 2. This is a single-shot weapon, it launches a low velocity explosive shell (grenade) with a blast effect that kills Common Infected and weaker Special Infected in its immediate vicinity. Any Infected who are not killed by the blast are injured and stumbled, excepting Chargers and Tanks who are immune to the stumbling effect.

A break-open design, the Grenade Launcher can only hold one shell at a time and has a long reload time. Since its leaf-type sights are permanently folded down and play no part in its operation, users seeking a distant target must use trial and guesswork to "walk" shells onto the target on account of this weapon's high-recoil looping trajectory. However, because its accuracy is identical to that of the Sniper Rifle when standing still, in theory the only thing required for pinpoint accuracy is the player's range estimation of the arching 40mm HE grenade.

The Grenade Launcher is unique in a number of ways. Primarily, it is not spawned with Tier 1 or Tier 2 weaponry but (like the Chainsaw) is found in peripheral rooms and structures (refer to the Notes section below for an exception). Additionally, it is encountered infrequently and players must not assume that one will reappear in the same place as previously. Finally, it has finite ammo that cannot be resupplied by ammo piles. Once a Grenade Launcher has expended its ammo, it must either be discarded or reloaded with an ammo upgrade (incendiary ammo or explosive ammo).

The Grenade Launcher can inflict heavy friendly fire damage on the user or nearby team members if its explosive projectile strikes a close range target or hard surface.

Official Description
Highly explosive shells from this weapon are guaranteed to blast infected to pieces within a tight radius, and stagger any infected immediately outside of that radius. It takes a while to reload, so make your shots count.

Tactics

 * Friendly fire damage on the Grenade Launcher is not too high on lower difficulties, but it becomes a formidable threat on higher difficulties. Great care is thus essential in closely confined spaces and when combat is moving to close quarter conditions; under such circumstances it is often desirable for the operator to switch to a secondary weapon.
 * If you are surrounded by a Horde or if a Special Infected is about to grab you, fire at your feet. The surrounding Horde will be vaporized or the Special Infected will probably either stumble or die. On lower difficulties, any self-damage caused will be insignificant. This ploy is not recommended on higher difficulties.
 * Self-inflicted friendly fire damage for the Grenade Launcher was increased on the PC version of Left 4 Dead 2 on 9th June 2010 according to player feedback. Friendly fire on teammates from the Grenade Launcher is apparently unchanged.
 * If your intended target is several feet away and a Horde of Common Infected are right in front of you, do NOT fire the Grenade Launcher as the splash damage is immense and the Common Infected may overwhelm you if too much health was lost. Try to shove them away or switch to a sidearm/melee weapon.
 * Since the grenade is contact fused, it makes excellent sense to aim at hard surfaces in close proximity to the operator's desired target: for example, aiming at a fence that masses of zombies are trying to climb up or the walls of a tight alley choke point (in this regard, refer to the following two Notes for important blast effect data).
 * The Grenade Launcher is less effective in wide open spaces as its explosive effect is more diffused and its explosive power is weaker in comparison to a propane tank or pipe bomb.
 * If shooting directly at a group of rushing Common Infected, the grenade will hit a few in the front and only stumble the ones behind them. To get the most out of a single grenade on a massed target it is best to shoot from above and aim for the middle of the Horde to kill the most Infected. The projectile's low velocity also requires the operator to lead a moving target.
 * The Grenade Launcher is ideal for mopping up clumps of stationary Common Infected in an open area, such as those encountered in the Whispering Oaks' Kiddie Land.
 * The Bile bomb works particularly well when used in conjunction with the Grenade Launcher. A Bile bomb creates a large group of Common Infected at a safe distance that can then be obliterated the Grenade Launcher. Basically having a Pipe Bomb's effects.
 * The Grenade Launcher stumbles Special Infected that are pinning a teammate at a point of no return or at a distance. Since the pinned player is immune to blast damage, the operator can fire with a clear conscience.
 * If a Smoker has just ensnared you, it is easy to hit him with a grenade's blast radius (a direct hit or kill is not required) and save yourself, since the Grenade Launcher always has the same accuracy even when moving. Moreover, when a Smoker has caught a Survivor with his tongue, he cannot move to dodge the grenade.
 * While the Grenade Launcher does not do very much damage to a Witch (a direct hit will cause about 550 ~ 850 damage), it does stumble her. This means if a teammate disturbs her, she can be disorientated with a grenade, thereby allowing the offender to escape and make it easier for everyone to kill her. Witches can also be blasted with a grenade from a distance; in this way a team team can take her down very easily.
 * With a direct hit, the Grenade Launcher does 1000 damage to a Tank. If used in conjunction with a nearby propane tank or a gas can, the stumbled Tank will be placed at a distinct disadvantage whilst the player reloads.
 * In addition to the 1000 damage per shot on a Tank, flames from grenades provided via the use of incendiary ammo with the Grenade Launcher do not wear off on a Tank. A player can use this as a makeshift Molotov with a huge damage bonus.
 * This also pairs well with Chainsaw. The Chainsaw deals the same damage per attack—in a second. In a well-timed combination, the Tank can be defeated in mere seconds, if you attack a distracted Tank with a Chainsaw, it will kill the tank in 2 seconds after being shot by the Grenade.
 * In most cases, dual Pistols or the Magnum are better than melee weapons as backup secondary weapons, as they allow the operator to take down individual or small groups of Common Infected from a distance without the need to waste grenades.
 * However, sometimes it is better to have a melee weapon as a backup rather than the Pistols for close quarters combat against Hordes.
 * The Chainsaw is not recommended as a secondary weapon while using the Grenade Launcher. Both weapons cause high friendly fire damage, have limited ammunition that cannot be replaced, lack precision and long-distance capacities, and have long pauses during use (Grenade Launcher's reload and Chainsaw's draw times). A player is therefore generally better off with a more conventional backup weapon.
 * The laser sight confers no benefit to the Grenade Launcher since its shell always follows a slow, looping trajectory.
 * When using Incendiary or Explosive Ammo with the Grenade Launcher, the upgrade will give the operator one extra grenade. The Incendiary grenade will set nearby living Infected (of all types) on fire if they would otherwise have been stumbled. Explosive Ammo will give a slightly more potent blast, although it is hard to notice in practice.
 * The Grenade Launcher can be used to detonate static explosives such as the propane tank and the gas can. This can make it useful when setting up for a finale, although it makes the Grenade Launcher a hazard in Scavenge mode and in the finales of Dead Center and The Passing.
 * Experienced players are inclined to use it as a support weapon and ensure that teammates with other weapons provide cover whilst reloading.

Strengths
There is generally only one good reason to equip a grenade launcher for serious play:
 * It is capable of damaging and stunning targets behind cover. Strategies include:
 * Using explosions to safely root out Special Infected that are waiting to ambush survivors.
 * Extremely effective against troublesome Boomers when used in this regard.
 * Effective in Versus when used against infected players who employ ambush strategies.
 * Firing a grenade into an unexplored room before entering as to safely clear it out.
 * Be wary of accidentally detonating usable items such as gas cans that are out of view.
 * Using the arc of the grenade launcher's trajectory to fire over cover at targets.

The following strengths are superficial, but worth mentioning. They are not reasons to equip a grenade launcher:
 * Can destroy compressed Hordes in one or two shots.
 * Grenade explosions stumble all Special Infected except for Chargers and Tanks.

Shortcomings
It is ill-advisable to equip a grenade launcher while playing in a high difficulty setting. At this point, the grenade launcher's shortcomings outweigh its strengths for the following reasons:
 * The niche-nature of this weapon makes it better fit the role of a indirect-fire utility rather than an offensive or defensive weapon. Most weapons outclass the grenade launcher in circumstances where direct-fire is desired.
 * Very high risk of friendly fire due to the large explosion radius. Multiple teammates can be injured or even incapacitated by a misplaced shot.
 * The risk factor increases exponentially with higher difficulties and as the distance to the target closes.
 * It is a horrible primary weapon, it is best to use a pistol or a magnum as your primary

Other shortcomings that are worth mentioning:
 * Single shot before a lengthy reload time makes this weapon poor for self-defense.
 * In an open environment the grenade launcher is only useful at medium ranges.
 * Specifically, where the target is far enough that friendly fire is not a concern and guesswork isn't required to land a shot that is better made with a rifle.
 * Ammunition cannot be replenished by ammunition piles. This is not helped by the fact that the grenade launcher is uncommon to find.
 * Grenade explosions do not stumble Chargers orTanks.

Videos

 * Swamp Fever Grenade Launcher Gameplay
 * PAX Dark Carnival Grenade Launcher Gameplay
 * Whitaker holding an M79 grenade launcher on Chapter 2 of Dead Center
 * Grenade launcher in action