The M203 grenade launcher is a single-shot, breach-loading, 40 mm grenade launcher that attaches to the bottom of the M16 assault rifle or M4 carbine. It was designed to be a more portable and versatile replacement for the M79 stand-alone grenade launcher. Variations of the weapon include models that can easily mount to any standard RAS (Rail Accessory System). The M203 can fire grenades of the following types: high-explosive, smoke, illuminating, buckshot direct fire, high-explosive Dual-purpose, CS gas, and training.

	The M203 Grenade Launcher

The M203 is very easy to operate. You simply push the barrel forward to expose the breach, load in your choice of 40 mm grenade, lock the barrel back into its original position, aim, and fire (rinse, repeat). As mentioned in the introduction, the M203 is designed to attach to the bottom of an M16 or M4 rifle. It can be fired independently of the rifle, but this is both very difficult and potentially dangerous. One of the best uses of the M203 in the zombie apocalypse is that it can be used to launch illuminating rounds or flares. This can prove useful in illuminating an open field or parking lot where light may be scarce. On the downside, its main ammunition is the high explosive grenade. As with most grenades, they rely on shrapnel for their lethality, and unless you, by luck, manage to lodge a piece of metal in a zombie's cranium, the M203 does little more than add an unnecessary 3 pounds (1.36 kg) to the front of your weapon.

The M203 was designed to be an easily portable and versatile grenade launcher, and it does its job "okay". Unfortunately, it is noted as being slow and cumbersome to reload, as well as somewhat inaccurate as it is chunkily mounted to the bottom of its M4 or M16 host. The sighting system it uses is also often set up incorrectly and is hard to read. However, the M203 has a fairly simple operating mechanism, which makes it very reliable and simple to maintain, and it will get the grenade easily from point A to point B.

The M203 features a wide variety of ammunition, each having a very specific and different use. High explosive rounds can be used to breach doors or fortified areas such as storage facilities, as well as eliminate encroaching zombies if necessary. However, this is highly ineffective. As mentioned earlier, one of the best uses of the M203 in the zombie apocalypse is that it can be used to launch illuminating rounds or flares. This can prove useful in illuminating an open field or parking lot where light may be scarce. Lastly, the large caliber buckshot can easily eliminate multiple hostile targets at one time. Unfortunately, there are several inherent problems with the M203's 40 mm ammunition. Most of all, they are considered "Destructive Devices" and are therefore illegal to possess in the civilian market. This makes the stock piling of ammunition pre-apocalypse almost impossible. Also, with the exception of the high explosive rounds, the military has little use for the other variations of 40 mm ammunition rendering them scarce at best post-war. Possibly, the most major draw back of the 40 mm ammunition is its weight. A standard 40 mm grenade weighs in at a massive .5 pounds (.22 kg). As any grenadier will tell you, these things get heavy quickly, and if you are constantly on the move, you will feel the fatigue almost instantly.

	The M203 Grenade Launcher Mounted under an M4-A1

The M203's design is the essence of portability. It is designed to attach directly to the bottom on an M4 or M16 assault rifle, eliminating the need for it to be independently carried. Think of it in terms of the classic science fiction movie "Aliens". You only have 2 hands, and you have the option of bringing a large rifle with a grenade launcher, or a large flame thrower. Which do you take? Simple. Duct tape the weapons together, and bam, you have 3 guns for the price of one. This is exactly what an M203 is. If you already have an M16, you can simply attach an M203 to the bottom of it, and you are left with 2 guns for the price of one. Unfortunately, since use of the M203 is purely situational, you will be carrying a lot of unnecessary dead weight while it's not being used. This brings us to the ammunition. Each half pound (.22 kg) grenade is roughly the size of a small bottle of Tylenol®, making them excessively heavy and cumbersome to carry in mass quantity. Fortunately, M203 Grenade Launchers are standard military issue, so there are tons of neat options and accessories for making them just a little bit easier to carry.

As stated earlier, most grenades are fairly unreliable when talking about dispatching our undead foes. They do tend to do a lot of damage, but not the type required to render trauma to the head area. For the same weight and size that the standard load of 40 mm grenades takes up, you can easily carry hundreds of rounds of conventional ammunition, capable of killing dozens of zombies far more efficiently. However, high explosive grenades do find their place in performing other tasks such as breaching doors and clearing road blocks. The point is, High explosive grenade rounds are not the best choice for terminating a zombie, but if you don't mind carrying the extra weight of a loaded M203 under your gun, you might as well take it because there is no telling when it just might come in handy.