Originally manufactured by the Hydra-Matic Division of General Motors and remanufactured by J. Stemple of Groveport, Ohio (marked under grip). Most famous for its namesake automatic transmission, the Hydra-Matic Division produced two contract runs for the U.S. military using a technical data package from Colt by way of the Department of Defense. While many were made, most were destroyed at the end of their service life, the majority being saw cut and discarded as scrap. Post front and two leaf windage adjustable rear sights, with a three prong flash hider and bayonet lug on the "12" and "M (verified proof)" marked barrel, unmarked upper receiver with short casing deflector and oval forward assist, triangular handguard, checkered pistol grip, and a fixed buttstock with a ribbed buttplate. The receiver is fitted with a right handed "SAFE"/"SEMI"/"AUTO" selector, with "HYDRA-MATIC DIV./G.M. CORP./U.S.A./PROPERTY/OF U.S. GOVT./M16A1" on the left side of the magazine well over the caliber and serial number. The Stemple address has been added to the left side of the grip tang. The bolt and bolt carrier are both chrome plated, the former marked "M/P" and the latter being without forward assist serrations and featuring a "flat head" retention pin and a staked and chromed gas key.

Very fine as restored/remanufactured , with 95% of the matte gray phosphate finish, showing a number of light handling marks and some light edge wear. The stock is also excellent, with some light scratches. 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) that is classified as a "Curios or Relic" as defined in 27 CFR, 478.11. These weapons are still subject to the provisions of 18 U.S.C. Chapter 44 and 27 CFR part 479.