M653

The Colt M653 M16A1 Carbine was a variation of the CAR-15 that was derived from the M16A1.

History
Colt began development of the M653 Carbine as a carbine offshoot of the M16A1 that would act as the standardized sidearm of Commandos. It also had other variations, the M651, M652, and the M654, although only the M653 was sold in large amounts to the U.S. Armed Forces, and were purchased by the Army, Navy and Air Force, as well as the Malaysian Armed Forces in small numbers for special operations forces and security forces. It was also sold in large numbers to Israel during its Yom Kippur War in 1973, namely as part of the U.S. mission Operation Nickel Grass.

During the Peace Walker Incident in 1974, Big Boss and his mercenary unit, the Militaires Sans Frontieres, procured design specs on the M653 after stopping a missile attack on Mother Base. The MSF's R&D Team also made several modifications on the original model, such as giving it a suppressor, Grenade Launcher attachments, Smoke Grenade Launcher attachments and Shotgun attachments. The Peace Sentinels also made use of this weapon via its vehicle escort units.

Post-Peace Walker
The Israeli Defense Forces continue to use the M653, called CAR-15 by its users in the present day, as well as receiving various modifications to the gun.

In-game descriptions
"A carbine offshot of the M16, developed for use by commandos. It takes the superior capabilities of the original M16 and puts them into a lighter, more compact package. These qualities make it ideal for extended solo missions; as such it is the weapon of choice for many Special Forces units. The M653's easy handling allows for a more stable aim, resulting in a high firing accuracy. (Rank 4) Equipped with a limited-use suppressor. The suppressor will eventually wear out, so use it prudently."

- M653 description from Metal Gear Solid: Peace Walker

"A carbine offshot of the M16, developed for use by commandos. It takes the superior capabilities of the original M16 and puts them into a lighter, more compact package. These qualities make it ideal for extended solo missions; as such it is the weapon of choice for many Special Forces units. The M653's easy handling allows for a more stable aim, resulting in a high firing accuracy. A grenade launcher has been added to this model, improving its performance in combat against groups of enemies and larger, armored targets."

- M653 (w/ Grenade Launcher) description from Metal Gear Solid: Peace Walker

"A carbine offshot of the M16, developed for use by commandos. It takes the superior capabilities of the original M16 and puts them into a lighter, more compact package. These qualities make it ideal for extended solo missions; as such it is the weapon of choice for many Special Forces units. The M653's easy handling allows for a more stable aim, resulting in a high firing accuracy. This model has been modified with an extra underbarrel shotgun, greatly increasing its firepower and making it an effective weapon against both close- and long-range targets."

- M653 (w/ Shotgun) description from Metal Gear Solid: Peace Walker

"A carbine offshot of the M16, developed for use by commandos. It takes the superior capabilities of the original M16 and puts them into a lighter, more compact package. These qualities make it ideal for extended solo missions; as such it is the weapon of choice for many Special Forces units. The M653's easy handling allows for a more stable aim, resulting in a high firing accuracy. A smoke grenade launcher has been added to this model, which not only increases its direct attack power but also degrades the enemy's ability to track and engage targets, resulting in a much more versatile weapon."

- M653 (w/ Smoke Grenade Launcher) description from Metal Gear Solid: Peace Walker