Grenade Launcher

"Oh, I like this!"

- Rochelle "Time to make some zombie soup!"

- Nick

The Grenade Launcher is a primary weapon that made its debut in Left 4 Dead 2. 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 disorientated (stumbled) but Chargers and Tanks are immune to this 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 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. Firstly it is not spawned together with Tier 1 or Tier 2 weaponry but (like the Chainsaw) is found in peripheral rooms and structures (refer Notes section below for an exception). Secondly it is encountered infrequently and players must not assume that one will reappear in the same place as previously. Thirdly it has finite ammo and ammo cannot be resupplied from normal ammo piles. Once a Grenade Launcher has expended its ammo, it must be discarded or receive a modest augmentation from an ammo upgrade (e.g. incendiary ammo).

The Grenade Launcher can inflict heavy friendly fire damage on the user, nearby Survivors or 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 definitely stacks up and gets higher with difficulty. 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 Pistols or a melee weapon.
 * If you are surrounded by a Horde or if a Special Infected is about to grab you (Hunter, Jockey, or Charger), fire at your feet. The surrounding Horde will be vaporized or the Special Infected will most likely stumble or die as long as the player is not concerned about taking some damage. 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. It is still undergoing testing and may be changed accordingly in the future. Friendly fire on teammates from the Grenade Launcher is apparently unchanged.
 * 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 chokepoint (in this regard, refer 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 with the Grenade Launcher. A Bile bomb creates a large group of Common Infected at a safe distance that can then be obliterated with a barrage of explosive shells.
 * 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 starts to choke a player, it is easy to land a grenade on him and save one's self since the Grenade Launcher always has the same accuracy even when moving.
 * 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 team mate disturbs her, she can be disorientated by 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, incendiary grenades do not wear off on a tank. A player can use this as a makeshift molotov with a huge damage bonus.
 * In most cases, dual Pistols or the Magnum are better than the melee weapons as backup secondary weapons as they allow the operator to take down individual or small groups of Common Infected without the need to waste grenades. However, sometimes it is better to have a melee weapon on backup rather than the Pistols for close quarters combat against Hordes.
 * The Chainsaw is not recommended as a secondary weapon. Both weapons: cause high teammate damage (especially in melee); have limited ammunition that cannot be easily replaced; lack precision and long-distance capacities; and they 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 on fire nearby living Infected (of all types). 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 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.

Pros

 * Extremely powerful
 * Can take down the Horde in one or two shots
 * Comes into its own in Survival Mode and during times when camping is an advantage
 * Works well with melee weapons
 * Can be useful with Incendiary ammo, especially against Special Infected, like the Tank and Charger.
 * Direct hits can do serious damage to the Tank, often as much as 2,000 damage if done right.
 * When used properly with the arc, can hit targets from behind cover; however, it takes a lot of time to master.
 * Stumbles Special Infected when the shell explodes directly or close by.
 * Can be a very useful support weapon in a Finale static defense scenario: especially where the team has taken up an overlook position

Cons

 * It is contact fused - meaning that operators can easily injure themselves and team mates with rounds that fall short
 * Friendly fire risk―a whole team can be taken down with one misplaced shot
 * Long reload time
 * Useless in close quarters situations or confined settings
 * Aiming at medium to long ranges is a matter of trial ("walking" shells onto the target) and sheer guesswork
 * Ultra-long range "mortaring" is possible - but this is meaningless since targets beyond direct observation have not yet spawned
 * Takes the place of weapons that could potentially do more damage
 * Hunters and Jockeys may be hard to hit due to their sizes and leaping abilities
 * On Advanced and Expert difficulty, the Grenade Launcher's benefits are heavily out weighed by the downsides; most teams frown on the use of the Grenade Launcher unless in very skilled hands.
 * Ammo is limited to 30 shells with no possibility of replenishment.
 * Only one shot per each reload.
 * Waste of ammo to kill one Infected

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: http://www.youtube.com/watch?v=325a8SKVB9g