The AAI Close Assault Weapon System (CAWS) was a creation of AAI Corporation for the Naval Weapons Support Center of Crane, Indiana and sponsored by the Joint Service Small Arms Program during the 1980s. It was developed around the concept of an automatic shotgun-type weapon firing flechette-based ammunition through two fire modes. It was not adopted.
The complete AAI CAWS weighed 9lb when empty and had an overall length of 38.75 inches. A recoil-operated system was used in the firing action which resulted in recoil no greater than the standard-issue M16 assault rifle. Two modes of fire were built into the gun: semi-automatic and full-automatic (the latter operating at 450 rounds-per-minute).
The straight, detachable magazine was inserted under the action in the usual way and held twelve ready-to-fire shells specifically developed for the gun. The shells were of a anti-personnel flechette design (eight 1-gram flechettes to a shell)) intended to incapacitate subjects at close range with penetration values up to 3" of wood and 1/8" of steel sheeting. In testing, all eight of the fired flechettes stayed within a 13-foot radius, showcasing the inherent accuracy of this weapon. Standard, commercial 12-gauge ammunition types were also supported. Range was out to 495 feet.
Sighting was through a front/rear iron arrangement with an optional optics set over the receiver being supported. The bulk of the receiver was slab-sided and relatively featureless save for the usual controls found on automatic weapons (charging handle, fire selector switch). The shoulder stock was reminiscent of the M16 rifle and the forend was perforated to allow for heat dissipation of the hot barrel with an under-barrel section used to protect the firer's supporting hand. The muzzle included a large brake.