M16A4

The M16A4 is an selective-fire assault rifle capable of semi-automatic and three-round burst firing modes, and is an updated version of the M16A2 rifle. The M16A4 rifle differs from the M16A2 in that it has a MIL-STD-1913 Picatinny rail under the removable carrying handle which allows different types of optics to be mounted on the top of the receiver. There are also Picatinny rails mounted on the handguard to allow lasers, flashlights, foregrips, and grenade launchers. It is the current standard issue rifle of the US Marine Corps and some US Army units. The US military purchases M16A4s from both Colt and FN Manufacturing. The M16A4 is light and accurate, but requires frequent cleaning, partially because it is susceptible to dirt, but also because its internal mechanism lacks a piston; the gases strike the bolt of the rifle directly. This method of operation results in a lighter rifle, but causes reliability issues, as carbon is blown into the chamber of the weapon, resulting in frequent fouling.

Game Info
In the single player campaign of Call of Duty 4: Modern Warfare, the M16A4 can only be picked up during the USMC levels. It is dropped occasionally (and rarely with the M203 grenade launcher) by incapacitated Marines and always with iron sights. The M16A4, in single player, has a fully automatic firing mode, which is inaccurate, as the real-life M16A4 does not feature full-automatic fire.

In multiplayer, the M16A4 is available at level 1. It is powerful and accurate and fires in three-round bursts. It can be fitted with a suppressor, red dot sight, ACOG, and M203 grenade launcher. The weapon is useful at any range, though the practicality of three-round burst fire at close range is disputable. The M16 is sometimes considered overpowered, because of its ability to drop an enemy in one burst if the perk "stopping power" is used.