AAI ACR

The AAI ACR was a prototype rifle that AAI Corporation built for the United States Army's Advanced Combat Rifle program of the 1980s. The Army contracted AAI alongside Ares, Colt, Heckler and Koch, McDonnell Douglas and Steyr-Mannlicher to look for a successor to the M16, aiming for a higher probability of hitting a target with the first shot. AAI's entry refined its earlier flechette-firing rifle, using a sabotted 5.56x45mm cartridge that carried a small dart-like flechette. The design fired only a three-round burst, which the source says was probably produced by a triple-chamber breech in a gas-operated action, and it needed a flash hider and sound suppressor to tame the blast and noise. A weak point was that the chamber could still accept ordinary 5.56x45mm NATO rounds, so proprietary magazines were used to keep the wrong ammunition out. Trials ran from 1989 to 1990, no entrant met the first-hit requirement in full, and the program ended in April 1990.