Introduced in 1967, the M16A1 (aka the Model 603) would be the standard issue rifle for the United States Army and Marine Corps until the 1980s. Developed from end-user feedback on the M16, the M16A1 introduced the "fenced" magazine catch to reduce the risk of accidentally ejecting the magazine during handling or movement, the forward assist upper receiver and bolt to help close a bolt that is obstructed by fowling or residue, and other minor adjustments. Post front and two-leaf flip rear sights, with early pattern birdcage flash hider, "C MP C" barrel, ribbed round handguard, checkered pistol grip and a two-position telescoping buttstock. The right side of the upper receiver is marked "C H" below the windage adjustment dial, with the Rampant Colt, model marking, and address on the left side of the lower receiver. The selector is right handed, with "SAFE", "SEMI" and "AUTO" positions, all functional, and a one-piece buffer assembly is installed. The bolt and bolt carrier are both black finished, the latter marked "C". Provenance: The Dr. Robert Azar Collection

Excellent, with 98% of the original matte black phosphate finish. The replacement upper receiver shows a lighter tone than the lower, with some mild scuffing concentrated on the forward assist and a spot of black enamel on the left side of the barrel. Mild handling marks are present overall The buttstock has a good fit to the buffer tube. Mechanically excellent. NOTE: This weapon is a National Firearms Act (NFA), fully transferable Class 3, which is registered with the Bureau of Alcohol, Tobacco, Firearms and Explosives, (BATFE) under the provisions of 18 U.S.C. Chapter 44 and 27 CFR part 478.