The Colt M16A1 in its original Vietnam-era configuration with XM16E1 markings represents the most historically significant M16 variant. Original 'birdcage' flash suppressor, three-prong predecessor flash hiders, and early triangular handguards are distinguishing features of the earliest production. Type: Semi-Auto Rifle Action: Gas-Operated Caliber: 5.56x45mm Capacity: 20 Year introduced: 1967, USA Weight: 7.9 oz Overall length: 39.5" Status: Discontinued Military use: Yes Intended use: Military, Collector, Historical