ACR

The ACR, referred to as Masada in the game files, is an assault rifle featured in Call of Duty: Modern Warfare 2 and Call of Duty Online.

Campaign
The ACR is the main Assault Rifle used by the Roach during the Task Force 141 campaign missions, and is used by other Task Force 141 members and Ghost during some missions. It is first available to the player as an optional weapon in The Pit in the mission "S.S.D.D." It is also used in the mission "Cliffhanger", with a Red Dot Sight, Silencer, Heartbeat Sensor, and a unique Arctic camouflage that is mostly comprised of natural ice and snow. An ACR Grenadier version with an ACOG Scope and Grenade Launcher is used in "Takedown", while another version featuring Holographic Sight and Grenade Launcher is used in "Loose Ends". A version with a unique matte black finish and the same attachments as found in "Cliffhanger" can also be found in the mission "Just Like Old Times". It is possible to also receive an ACR from dead Shadow Company soldiers in their respective missions.

Multiplayer
In Multiplayer, the ACR is unlocked at Level 48. It is similar to the M4A1 but sacrifices rate of fire for having extremely low recoil. It carries 30 rounds in its magazine, deals 30 to 20 damage per shot, and has a rate of fire of 789 RPM. Although the ACR bounces when firing, this recoil is purely visual and the weapon has near-zero actual recoil as it resets almost perfectly before the next shot, making it ideal for long range combat without the need for burst firing. Its lower damage per second makes it somewhat weak in close quarters combat compared to other automatic weapons such as the TAR-21, F2000, and SMGs.

A versatile weapon, most Perks and Attachments work well with the ACR, especially Stopping Power, which helps make up for its low damage per round. With Stopping Power, it takes four shots to kill at long range (versus five without the perk), three shots at close range (versus four) and two headshots at close range (versus three without the perk). Another recommended attachment is the Silencer, as the ACR's range and accuracy makes it ideal for this attachment. The ACR is very useful at long ranges so therefore it excels in medium to large maps with long lines of sight such as Wasteland, Afghan, Highrise, Derail, Estate, Bailout, and Fuel. Its extremely low recoil means that it is very easy to use with the ACOG and Thermal Scopes, and wasting ammo due to missed shots is usually not an issue (although it also depends on the player's skill to aim well, especially on a moving target). The ACR tends to chew through ammo quickly much like the M4A1, but its accuracy makes missing shots a lesser issue. Also, the ACR is one of the most effective weapons in the game for reload canceling; the player does not even need to wait until the magazine is fully inserted into the rifle before ammo is replenished. Even without the reload cancel, the reload time is still very quick at only two seconds.

In terms of damage output per second, the ACR's low damage and moderate rate of fire makes it the least powerful assault rifle in the game. Still, its effectively non-existent recoil ensures all properly aimed shots are on target, allowing for more expedient kills. Because of these features, it is a very popular assault rifle in Call of Duty: Modern Warfare 2.

Weapon Attachments

 * Grenade Launcher
 * Red Dot Sight
 * Silencer
 * ACOG Scope
 * FMJ
 * Shotgun
 * Holographic Sight
 * Heartbeat Sensor
 * Thermal Scope
 * Extended Mags

Trivia

 * On Infinity Ward's website, the ACR was voted the favorite assault rifle in Call of Duty: Modern Warfare 2.
 * The serial number of the ACR in Call of Duty: Modern Warfare 2 is 0091436. 91436 is the ZIP code for Encino, CA, where Infinity Ward is located. This can be seen on a few other weapons.
 * When this weapon has a Thermal Scope attached, the pick-up icon's text will read "ACR Thermal Sight" instead of "ACR Thermal Scope".
 * The ACR appears to be larger than any other assault rifle when seen from third person.
 * The ACR seems to be a preferred weapon of Task Force 141 operatives Ghost and Roach.
 * Interestingly, the ACR in Campaign and Spec Ops actually has more recoil than its multiplayer equivalent.
 * In Create-a-Class, the ACR can be seen in a black finish, but if no camouflage is added, it is gray on its camouflage-able parts. However, in "Just Like Old Times", the player can find black ACRs in the steam room where Shadow Company ambushes the player.
 * On the side of the ACR is written "CAL 5.56 EURO". This is best visible with Arctic Camouflage, but can be seen with any camouflage applied.
 * In the campaign, the ACR has a Holographic Sight and Digital Camouflage as seen in "Loose Ends". This ACR's Holographic has zoom level of an ACOG.
 * In "Cliffhanger", when the player enters the hangar with the ACR, the caked snow and ice melts off of it, revealing painted Unknown Arctic Camouflage underneath.
 * The ACR, along with the AK-47 and the M4A1, when they are equipped with a Grenade Launcher, it gives the name of "ACR Grenadier."
 * Oddly, in the Call of Duty: Modern Warfare 2 Official Strategy Guide, it describes the ACR as a "Semi-Automatic (Single Fire)" rifle, when in-game, it is a fully-automatic rifle.
 * The black ACRs in "Just Like Old Times" can hold up to 1260 rounds in reserve.