ACR

By the 21st Century, assault rifles were being designed with the intention of being adaptive, modular and compatible: adaptable to different combat roles, modular in that they were changeable between different caliber munitions, and compatible with different accessories/components. This concept was widely demonstrated by the AR-15 platform used by civilian firearm enthusiasts, who outfitted their AR-15 rifles with various aftermarket receivers and parts. AR-15 rifles are considered extremely modular and adaptable to a variety of different functions, uses, and calibers. Designed by Magpul Industries, Remington Arms, and Bushmaster Arms, the Adaptive Combat Rifle (ACR) (previously known as the Masada) was presented to the U.S. military with this concept in mind. Designed in 2006 and presented to the US Army on an Industry Day in 2008, the ACR demonstrated current carbine technology and competed to replace the M4 Carbine in US military service during the 2011 Individual Carbine competition. The military version of the ACR is produced by Remington Arms. The Remington ACR is classified as a gas-operated, selective-fire rifle. It makes use of the short-stroke gas piston system from Stoner's AR-18, and is able to achieve a cyclic rate of 650 to 700 rounds per minute. The Remington ACR chambers the standard 5.56×45mm NATO cartridge, and could be modified to chamber the .300 BLK and 6.8×43mm Remington SPC cartridges (the 6.8 SPC being specially designed for U.S. special forces usage). The rifle can be fed by Magpul's own 30-round capacity PMags or all M16 style magazines. The fire selector lever is located above the pistol grip, and it toggles between fully and semi automatic as well as functioning as a safety. The charging handle is placed in a manner similar to FN's SCAR, where it is a horizontal reciprocating curved piece located above the magazine well. The magazine release is located just above the trigger. All the features of the ACR can be moved to either side of the rifle, making it fully ambidextrous. Empty brass cases can only eject to the right, but a deflector is installed to deflect spent brass away from a left handed user's face. The ACR is advertised as being adaptive, meaning the rifle can be quickly disassembled. Parts can be replaced and swapped quickly in the field without the use of tools. To switch between firing calibers, the user simply has to replace the bolt head and barrel. Having access to different length barrels and foldable/extendable stocks, the ACR can be quickly modified into a carbine, PDW, and DMR variant from the standard assault rifle configuration. Other features include various polymer components to cut down on weight, and a monolithic Picatinny rail along the top of the rifle for attaching optics. Additional Picatinny rails can also be installed on the Remington ACR's handguard to allow for the mounting of other compatible accessories. The Individual Carbine competition was prematurely cancelled with no winner chosen, so the ACR did not win despite demonstrating all of its selling points. As a result, the rifle itself did not enter mass production. However, in 2008 Bushmaster International entered into a licensing agreement with Magpul whereby they would take over production, future development, and sales of the ACR. Bushmaster produced a semi-automatic version known as the Bushmaster ACR and released it onto the commercial market to civilian gun enthusiasts. Bushmaster also produced various aftermarket conversion kits, allowing the Bushmaster ACR to chamber calibers such as 6.5mm Grendel and 7.62×39mm Soviet.