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  Colt M4A1 Carbine
Special Forces
M9 Pistol
SPR Rifle
Thermite Grenade

U.S. Weapons


Manufacturer: Colt Manufacturing, USA
Caliber: 5.56X45mm NATO (.223 Remington)
Length: (Stock extended) 33.0in (Stock retracted) 29.8in
Weight Unloaded: 5.5lb
Barrel: 14.5in, 6 groove, 1:7 right hand twist
Magazine: 30rd detachable box
Muzzle velocity: ~2900fps
Cyclic Rate: 750-900rpm
Modes of Fire: Semi auto, fully automatic

The M4A1 carbine is quite possibly one of the finest assault weapons in the world today. It is a direct descendant of the M16 rifle and the CAR-15 carbine of the Vietnam era, and will probably form the basis of the United States' main infantry weapon for the next ten to fifteen years.

The M4A1 has its roots in the Vietnam War. Shortly after the M16 was issued to US troops, it became evident that while the M16 was a light, handy rifle, a even lighter, shorter, handier carbine would be useful for special operations forces. Armalite had just handed off production of the M16 rifle to Colt, and cold began to make the CAR-15 (also known as the XM177) for the US military. The CAR-15, also commonly known as the "Commando," had a 10 inch long barrel and a collapsing stock.

These short rifles looked very sexy and dangerous and lethal, but problems almost immediately began to crop up. First and foremost, the short barrel meant that a short gas tube had to be used. Due to the cropping of the gas tube, there was often not enough gas pressure to cycle the action. In addition, the short barrel could only launch a 55gr projectile at 2700fps. 5.56mm ammunition requires a high velocity in order to achieve maximum stopping power. At extremely close ranges, the 10" barrel was adequate, but only out to maybe 50 meters.

Colt replaced the 10 inch barrel with an 11.5" barrel and created the XM177E2, which solved some of the reliability problems, but didn't do much to increase the wounding potential of the carbine. This carbine was also dropped from production.

As time passed, several other variants of short-barrelled M16's appeared and vanished. A short version of the M16A2 became popular in the 1980's, but was never officially adopted any mainly issued only to troops who needed a short weapon - drivers, dog handlers, and the like. It was during this time that the 14.5" barrel was arrived at as a good compromise between compactness, reliability, and wounding potential.

In 1994, the M4 and M4A1 carbines were finally adopted by the US Military. The M4 and M4A1 variants are the same, except for the fact that the M4 has a safe/semi/three-round burst mechanism (using the familiar rachet mechanism of the M16A2), while the M4A1 has a safe/semi/full automatic mechanism. While early models of the M4 series used the same receiver as the M16A2 rifle, final production models use a flat-top receiver that has an integral Picatinny rail that allows optical, red-dot, or a carry handle with iron sights (similar to standard M16A2 sights) sights to be easily attached.

The M4 series carbine also has a 7 3/4" long hand guard with double heat shields to better protect the user's hand from the barrel heating up rapidly in automatic fire. The buttstock is a four-position (closed, 1/2, 3/4, and open) collapsible stock that allows for a compact weapon, fully six inches shorter than a full-size M16A2. The stock also allows users to wear thick body armor and gear, yet still be able to shoulder the weapon easily. The M4 carbine also has an enlarged gas port as compared to the M16. This aids in reliability.

The M4 carbine has a curiously shaped barrel. The barrel is extremely lightweight in profile, and has a groove cut in the barrel just in front of the front sight post to accomodate an M203 grenade launcher. Some view this lightweight barrel as a mistake in design, as the light weight means that the barrel will heat up rapidly and not be as accurate at longer ranges under sustained fire. While this is true, others point out that the M4 is intended to be used at mainly shorter ranges where accuracy won't be as much as a problem. The lighter weight barrel also makes the weapon lighter and quicker to swing about.

Perhaps one of the greatest advantages of the M4 carbine is its endless ability to be upgraded through the use of accessories. Knights Armament Inc. has developed a forearm for the M4 carbine that adds four more Picatinny rails. This allows gear such as foregrips, lights, laser designators, sights, and other toys to be quickly and easily added to the weapon. In addition, as mentioned before, the M203 40mm grenade launcher can be easily clamped onto the M4 carbine. When too much is too much is left up to the individual using the actual rifle.

The M4 carbine has been well received in not only the military, but in SWAT teams and the like. The weapon is compact, lethal, very accurate out to about 300 yards, reliable. It is making strong inroads against submachine guns such as the Heckler and Koch MP5 since the M4 is almost as compact, and yet can punch through soft body armor. Yet, it is still capable of making lethal shots almost as well as the full-sized M16A2. The M4 carbine is the basis of the next-generation Land Warrior program for the US military. In short, the M4 will be around for a while.