M16A4

The M16A4 is a 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 and simpler rifle, but causes reliability issues, as carbon is blown into the chamber of the weapon, resulting in frequent fouling.

History
The M16 assault rifle was originally designed in 1957 by Eugene Stoner as the AR-15, a 5.56x45mm variant of his earlier, and unpopular, AR-10 rifle in 7.62x51mm. It was accepted by the U.S. Army in 1961 and saw use in Vietnam, where it was generally unpopular due to fouling problems caused by the weapon's direct gas impingement system and the adoption by the United States Army of a new type of propellant the weapon wasn't originally designed to use. In addition, the weapon was distributed along with literature that stated that minimal or no cleaning was necessary, which turned out to be false. This led to the design and adoption of the M16A1, which featured a forward assist. This feature, combined with regular maintenance of the weapon, helped alleviate jams and other problems caused by fouling.

The M16A2 rifle was adopted in the 1980s. The M16A2 was followed by the M16A3, which reverted to the full-automatic option. It was not adopted in large numbers.

The current version, the M16A4, features a Picatinny rail for different sighting solutions, and retains the three-round burst option of the M16A2, replacing the full-auto option of the M16A3. It also features a rail under the handguard for other attachments.

The M16A4 and its variant, the M4 Carbine, are in wide use by United States military forces,particularly U.S.Marine Corps and a few U.S.Army units(M16A4),while the Army mostly uses the M4A1 and older M16A2s,and the M4 doesn't see widespread use by the Marines.

Call of Duty 4
In Singleplayer, the M16A4 can only be picked up during War Pig (level). It is dropped occasionally (sometimes with the M203 grenade launcher) by dead Marines, and always uses iron sights. The M16A4 in singleplayer has a full automatic firing mode, which is inaccurate, as in reality the M16A4 does not feature full-automatic fire. However, the M16A3 does feature a full-automatic fire mode so it is possible that the weapon on this level is just mislabeled as an M16A4.Another fact is that the weapon model uses M16A1 lower receiver,while it has original M16A4 upper receiver;this explains why the rifle can fire fully-automatic in Single Player

In Multiplayer, the M16A4 is available at level 1 and fires in three-round bursts. The M16 can be fitted with a suppressor, red dot sight, ACOG, and M203 grenade launcher. It is also fairly similar to the M4 Carbine, as it has the same appearance, the same iron sights, and they also share ammo with each other, as well as with the G36C.

Using
It is often recommended to fire at a distance, as the M16's three-round burst is not very effective in close quarters combat. Steady Aim does a good job at making up for this, but should not be heavily relied upon. When used with Stopping Power, the M16 is able to kill in one burst at any range provided that all three shots hit the target (only two are needed at medium and close range) and the target is not behind a wall or using Juggernaut. For this reason, along with the fact that there is no idle sway, little recoil, and a short reload time, it is widely considered to be an overpowered gun. Contrary to popular belief, Double Tap does have an effect on the M16A4, as it decreases the delay between the firing of each of the three bullets in a single burst and decreases the amount of time between bursts. Simply put, all of the bullets fired in a single burst are now fired at almost the exact same time. This can be somewhat useful in many situations, as there is a higher chance of all three bullets hitting the target. Stopping Power is still considerably better, except in Hardcore modes.

Trivia

 * The words "BLUE4" and "Property of U.S. Government, Caliber 5.55x45mm NATO, M4A1 Carbine" in bold blue letters is visible on the side of the M16A4. The M16 fires a 5.56mm round, not 5.55mm, and is not an M4 Carbine as it says. Infinity Ward most likely used the same weapon skin for both the M4 and the M16A4.


 * It is important to note that individual bursts fire as fast as the P90 and M249, making it an unusually fast Assault Rifle.


 * In Multiplayer, if you attach the grenade launcher to the M16A4, it turns into an M16A2/A4 hybrid. The heat shield added over the handguard was the standard mount for the M203 for A2 rifles. If it were attached to an M16A4, the launcher would be mounted under the Knights Armament rail system. Yet still has the A4 removable carry handle making it a cross between A4 and A2.


 * This is a great weapon to start for new players but very deadly for experienced players.


 * In Singleplayer, if you enable the "Infinite Ammo" cheat and pick up a M16 with the M203 grenade launcher, the full-automatic rate of fire of the grenade launcher rivals or slightly surpasses that of the M4A1. Curiously, the M203 on the M4 Carbine and the GP-25 on the AK-47 have much slower full-automatic rates of fire, about the same as a bolt action sniper, or the W1200.

Gameplay footage
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