A Rocket launcher is any weapon that launches a rocket-proppeled projectile. Rocket launchers come in various sizes, shapes and uses. Infantry variants include; Rocket-propelled grenades, recoilless anti-tank/infantry versions, anti-tank guided systems and portable air-defense launchers. Larger scale rockets include static versions of many infantry or vehicular systems, and also artillery or anti-air based systems carried on vehicles. Rocket launchers, like usages mentioned previously, can be used against infantry, light vehicles, armored vehicles, aircraft and ships, although many are only fit for certain roles.
A rocket launcher is a handy weapon best used against entrenched zombies, or groups of zombies at medium and long ranges.
Keep in mind that rocket launchers have several drawbacks.
The first one is it's accesibility. You're going to have a hard time obtaining these launchers. And a harder time keeping a working supply line of the rocket ammunition. Unless one have cleared a federal background check and/or military training, posession is not allowed. If you are lucky enough to obtain it from a fallen soldier, or picked it up from downed military vehicles, this is going to bring another issue out.
Can you use it? Inexperienced handling of the launcher can cause serious injuries and/or death. What if you don't know how to hold it correctly and accidentaly dropped the launch tube, crushed your foot and rendered you immobilized? How if you don't know the correct stance before launching it? You could broke your arm, shoulder, or even blown off your ear drums. Or how if you don't know about the effects of a backblast from the launch? The heat and fire of a rocket exhaust can probably cook a steak in one go. Never fire a rocket launcher indoor. If you don't know how to use one, just forget it and go look for some other weapons you know how to use.
The third drawback of a rocket launcher is it's weight. If it is disposables like an AT4, or the LAW, you can just throw it away whenever you're done with it. But multiple use launchers like RPG must be carried at all times. What if you are out of ammunition? It's just going to be a useless pipe that does nothing rather than an effective tool of killing, which brings out it's fourth drawback;
Is it really effective to use against zombies? Maybe rocket launchers are all big and bad, but remember, we are not fighting humans here. Zombies have different characteristic than humans. Their blood's thicker than regular human, and they have increased endurance. Doesn't matter what explosions do to humans, zombies will have difference reactions. An HEDP rocket fired at a horde will take out out one or two zombies, and severe the limbs of a few, but that is it, compared to a rifle that can kill zombies with quick shots to the head. Remember that zombies will continue their struggle even with their limbs off, where humans will die. The right tactic is required to utilize rocket launcher effectively in a combat action against zombies. For example, a round fired at a pillar of a building that will bring down the entire structure upon a horde is better than a round directed straight at the horde itself.
However there are times when rocket launchers will come to a use. For example when you need to destroy a structure to cover or make your escape, that's when you need a rocket launcher. Bandits using cars to raid other survivors? Just blast those soft skins with an HE rocket. a rocket launcher is also a useful weapon of intimidation since one trigger pull is capable of obliterating a whole group.
The RPG-2 is a Russian rocket-propelled grenade launcher which was developed during World War II and entered service in 1949. It was widely used due to its simplicity and cost, and it was also very robust. However, it only had a maximum range of 150 meters and was inaccurate even within its range. Coupled with the advancement in armor technology by NATO during the Cold War, the RPG-2 was eventually replaced in the 1960s by the much more effective RPG-7.
The RPG-2 fired the PG-2 HEAT round, and did not have any round effective against infantry. It could penetrate armor of up to 180 millimeters.
Acquiring an RPG-2 is quite difficult in most nations of the world. As it is an RPG, its sale is banned in many countries, and most militaries have officially replaced it, so it would not be widely deployed during a zombie outbreak. Even then, it only has AT rounds, so its use would be very limited if at all. The only users of the rocket on any sizable scale would be militia and guerilla groups in Africa and the Middle East, who have inventories of the RPG-2 on hand. Overall, it's not best to look for one, as there are better weapons in most cases than rocket launchers as a whole.
The RPG-7 is a Russian rocket-propelled grenade launcher which was developed in 1961 to replace aging systems like the RPG-2. The RPG-7 is very widely used because of its cost, simplicity, the number manufactered and its durability. Original RPG-7s were only effective at about 300m maximum, though they're often used at closer ranges. Although modern armor has better survivability against rockets like the RPG-7, it has been upgraded to become more accurate at range and is still very powerful against many targets. The RPG-7's oldest rockets also have about 10 inches of armor penetration, while newer ones have nearly double.
The RPG-7, being quite versatile, has five different projectiles developed for it. The most common, the PG-7V has about 260mm of penetration. The upgraded PG-7VL have 500mm of penetration. Both of these projectiles are conventional anti-vehicular warheads and can take out even heavy armor. There is also a tandem AT warhead (The PG-7VR) which is meant to be more effective against reactive armor. It also has an extra 100mm of penetration for targets without reactive armor. The RPG-7 has also been adopted for anti-infantry use, with OG-7V fragmentation rounds, useful for targets holed up in buildings, and TBG-7V thermobaric rounds.
Unlike the RPG-2, the RPG-7 is a very widely adopted RPG. Around 40 countries use the RPG, including Russia (who still deploys it widely) and China. The RPG-7 is very common in South American, African and Asian nations, and even some Western nations have adopted it (Although more limitedly). The RPG-7 is very easy to mantain compared to most rocket launchers, and is also effective against a wide variety of targets. Chances are, if you are anywhere (Except places like West Europe or the US) you will probably find military units deploying RPG-7s against undead. Still, they are quite difficult to acquire before any disaster scenario.
The Panzerfaust is a very light anti-armor weapon developed in Nazi Germany during World War II. It was deployed on many fronts starting in 1942, and became very widespread with the german soldiers. Panzerfaust rocket launchers created the design concepts for many of the rocket systems of today (Including the RPG series and M-72 series). The Panzerfaust was mainly meant for light vehicles, although Allied heavy armor was still pretty light compared to their effective range, so with upgrades it was able to continue service throughout the war.
The Panzerfaust had a very limited range for its projectiles. The Panzerfaust 30 "klein" (the original model - "Klein" meaning "Small") only had 30m of range. However, this was coupled by its ability to penetrate 140mm of armor. The next development, the Panzerfaust 30, had the same range of 30m but had 200mm of armor penetration. In 1944, the most common variant, the Panzerfaust 60 was produced. The PzF60 had 60m of max range (like the namesake). The weapon also had 200mm of armor penetration, like the PzF30. The final, and most upgraded version produced was the Panzerfaust 100. The PzF100 had a max range of about 100m, and also had a slight armor penetration upgrade to 220mm of armor penetration. A PzF250 variant was under production, but Germany had been defeated before its completion.
The Panzerfaust was captured in very large numbers by many armies after the war's completion, and used in some conflicts in the years afterward, though it was mostly just used for research. By the 1950s, the weapon had no armies which used it in standard service. The weapon is still possible to be found at museums, though those are unable to function (To prevent a disaster). Different Panzerfausts have appeared in some conflicts even to today, but they are very rare and are likely just used because nothing else is available at the time.
The M-72 LAW (Light Anti-Armor Weapon) is an American unguided AT weapon. It was developed in the early 1960s and was entered into service in 1963, replacing old World War II era weapons like the M31 HEAT rifle grenade (Ones used on M1 Garand and M14 rifles) and M20 Bazookas. Many western nations have used this weapon since its development, although it has been widely reduced in usage. M72A2's (The most common variant) had a 66mm AT warhead which could penetrate up to eight inches of armor. Many upgrades followed the initial production of the LAW, adding better rocket motor mechanisms, improved assembly, improved anti-armor capability and safety upgrades.
The M-72 is a dedicated Anti-Armor weapon, although some upgrades have increased blast effectiveness in the rockets. The only rounds developed were HEAT rounds which have 200mm of armor penetration (Which is quite low against armored targets) and training rounds (Which are only tracer rockets and have no combat capability.) The rockets, however, are surprisingly effective against concrete bunkers, able to destroy up to two foot thick concrete, which is what the LAW was intended for (Destroying vietnamese bunkers, as they did not have many armored vehicles.).
The M-72 LAW was very widely adopted and used throughout the Cold War, but as it grew on, better weapons and better armor began to appear and the M-72 was losing effectiveness, even with constant upgrades. By the 1990s, most LAWs had been officially retired, although recently, some armies (Like the USMC and UK Army) have reintroduced modern versions of the LAW. It is, however, still common as a support weapon on standard squads and units, replacing heavier weapons meant for fire teams and dedicated AT teams. The weapon is disposable and easy to maintain, so it will not be uncommon, but its practical use against undead hordes would be limited with its AT capabilities. Still, the weapon is very well suited against light vehicles.
The AT-4 is a Swedish unguided AT weapon. The weapon entered service with most of its current users in the early to mid 1980s, replacing older weapons of similar role. Like the M-72 LAW, the rocket launcher is disposable, but is still very cheap to produce and acquire. The AT-4's main AT warhead can penetrate up to 16.5 inches of armor at up to 500m. The weapon is much more common than the M-72 LAW (Because of obvious advantages). Still, like the M-72, it cannot be reused after one shot, so all shots should count.
The AT-4 is also an Anti-Armor weapon, with improved capabilities as a firing support weapon against light vehicles, fortifications, bunkers, buildings and even personnel. Standard warheads penetrate about 420mm of armor, while HP rounds have 600mm of penetration. There is also an HEDP round developed specifically for light armor, bunkers, buildings and fortifications, which is the most commonly deployed variant. The AT-4 is very useful in the deployments as it also can be used as firing support against infantry.
The AT-4 is used in many Western, South American, African, European and Asian nations (making it diverse). The weapon is also very commonly seen in the inventories of units even on the squad level (Every USMC squad has at least one unit with one.) With increased effectiveness against personnel, it could possibly used to slow down the undead (Though it is single shot, so it is recommended to be saved for more lethal targets) and also against enemy vehicles. The weapon (like pretty much any other explosive) cannot be acquired legally in many parts of the world, though when any disaster (human conflict or not) occurs that a military using the weapon is deployed into, they will be using this, so it will not be hard to acquire.