The AMS-3 Ace, more formally known as the Special Applications Rifle, or Ace, is a Terran 14.5 mm Calibur anti-material sniper rifle.
The AMS-3 is a semi-automatic, pneumatic gas-operated rifle that fires 14.5x114mm ammunition from a four-round detachable box magazine. It can be fitted with high power rounds, which can "take the head off a Zealot at 2,000 yards." The ejection port is on the right side of the weapon and the charging handle is on the left side.
Unlike most other models of the AMS series, this variant features a thumbhole stock instead of a pistol grip, and its body sports a black and navy blue finish in addition to the gray of its successors. Also unlike its successors, it can be seen utilizing a sling-mount.
As an anti-material sniper, the Ace excels at penetrating enemy shielding and energy barriers to strike the target directly. The Ace remains accurate out to 1800 meters.