M16A3

The M16A3 is a selective-fire assault rifle developed by Colt. It is a variant of the M16A2, primarily distinguished by its full-automatic fire capability, as opposed to the M16A2's three-round burst. The M16A3 retains the direct impingement gas system and the 5.56x45mm NATO cartridge common to the M16 family.

Its upper receiver features a Picatinny rail for mounting optics and other accessories, a significant departure from the fixed carrying handle of earlier M16 models. While the M16A2 uses a 1:7 inch rifling twist, the M16A3 is often found with a 1:9 inch twist, which can offer better accuracy with a wider range of bullet weights.

The M16A3 saw limited adoption by some United States Navy and Marine Corps units. However, it was largely superseded by the M16A4, which features a detachable carrying handle and a different rail system. The M16A3 is a reliable and accurate rifle, and its full-automatic fire mode makes it more versatile in certain combat scenarios compared to the burst-fire M16A2. Its production was relatively short-lived, making it less common than other M16 variants.