ACR

The Remington ACR (Adaptive Combat Rifle), is a modern day assault rifle. It is an updated version of the Masada Adaptive Combat Weapon System, which was made by Magpul prior to their licensing agreement with Bushmaster, and later Remington. The weapon borrows traits from other firearms, most notably the ambidextrous operating handle in a forward position, similar to the SCAR. Its deisgn comes from numerous firearms, especially the AR-18, an updated version of the AR-15 (the original M16 design) that was more reliable. Although the ACR is intended to fire with 5.56x45mm ammunition and uses M16 barrels, the weapon can have M16 type magazines inserted as well as 7.62x39mm ammunition due to the firearm's modular construction, as well as other intermediate rounds popular with civilian shooters such as the 6.8mm SPC and 6.5mm Grendal. The Remington ACR was a candidate for the army's industry day, this and along with the HK416, FN SCAR, Barrett REC7, LWRC M6a2 and Colt ACCM (Colt's improved piston M4). The reason for industry day was to find a future replacement for the M4 carbine. The army is planning to field the last of its M4s in 2010.

Call of Duty: Modern Warfare 2
Not much is known about the ACR at the moment, but it is known that it is the starting weapon in Cliffhanger, Takedown and presumably other Task Force 141 levels. It has been seen with an ACOG Scope, M203 Grenade Launcher, Red Dot Sight, Suppressor and Heartbeat Sensor. It also appears that it uses a similar reload animation as the M4 from the original Modern Warfare. It is able to hold at least 600 rounds of extra ammo, not including the loaded magazine, in Spec Ops.