Staff Writer (Updated: 5/22/2015):
For its ACR, Steyr elected to use a similar bullpup configuration resembling their popular Steyr AUG assault rifle series. The bullpup arrangement merely identified the ACR as a weapon with its action and magazine feed located aft of the trigger group. Such an arrangement then allowed a full-length barrel to be utilized though in a more compact assault weapon body - the action nestled within the enlarged stock which was tucked away into the shoulder when firing. As with the AUG, the ACR was given a largely plastic body with metal internals to minimize both manufacture cost and overall carry weight. The weapon body included a two-piece plastic covering, one set over the main portion of the frame and the other housing the stock. The grip and trigger group were centralized along the bottom of the frame. The forend was wholly shrouded over and doubled as the foregrip and heatshield. The barrel muzzle was slotted in the M16 style and protruded only a short distance from the plastic body. Straight, proprietary plastic transparent magazines were inserted into the base of the stock, a magazine release button just aft of the feed well. Sling loops were located at the top of the shoulder stock and along the left side of the forend for shoulder strap usage. Over the top of the rifle was a two-gap rib assembly which acted primarily as a basic sighting device and could serve as an ad hoc carrying handle. To this assembly could be fitted optics as needed. A pull-type, spring-loaded charging handle was set at the rear of the sighting assembly as in the M16 and simply pulled back to cock the weapon. Spent cartridges were ejected through a port found under the stock between the magazine well and pistol grip. Overall, the ACR proved a clean and somewhat futuristic assault weapon design worthy of 21st Century warfare. As with the M16, the Steyr ACR utilized a gas-operated system in which a sleeve, wrapped around the barrel assembly, was driven rearwards during the action and this was mated to a vertically-sliding chamber managing the cartridge function.