The ACR, or Adaptive Combat Rifle, is an American-made assault rifle featured in. It fires a variety of cartridges like the 5.56x45mm NATO, 6.8mm Remington SPC, and even the Russian 7.62x39mm. The ACR is manufactured by Remington and Bushmaster. Remington produces the military version, capable of selective fire, and Bushmaster produces the civilian version, which is semi-auto only.