The M16A3 is a variant of the M16A2 issued primarily to the US Navy, featuring a flat-top upper receiver with Picatinny rail and a full-auto fire mode instead of the M16A2's burst. Relatively rare compared to other M16 variants. Type: Semi-Auto Rifle Action: Gas-Operated Caliber: 5.56x45mm Capacity: 30 Year introduced: 1994, USA Weight: 8.8 oz Overall length: 39.6" Status: Discontinued Military use: Yes Intended use: Military, Service Rifle