Originally manufactured as an AR-180 semi-automatic rifle by Sterling for Armalite, this rifle was upgraded to full automatic by Pearl Manufacturing. Armalite's follow-up to the AR-15, the AR-18/180 failed to gain deep market penetration, though many of the features (piston drive operation, ambidextrous fire controls, and a folding stock) would become popular upgrades to the AR-15 in later years. Adjustable post front and two-leaf peep rear sights, with a three prong flash hider and British commercial proofs on the barrel, ribbed and ventilated handguard, integral scope block on the AR-180/Sterling marked upper receiver, and the Pearl "PMC" mark on the left side of the lower receiver. The selector stops on the lower position have been cut down and rewelded to permit three-position operation, with "AUTO" added to the appropriate area, the interior of the upper receiver has been cut and reshaped to house the safety sear, and the bolt carrier has been altered to interface with the sear. Fitted with a smooth pistol grip and a side folding buttstock with ribbed buttplate. Magazine absent.

Very fine as converted and refinished, with 90% of the current black and blue finish, showing a rougher texture to the lower receiver, scattered light scratching and handling marks, and a bright, strong blue on the barrel. Mild pitting is present on the charging handle, and the retention stud for the folding stock has been broken off (but is included with the lot). The furniture is very good, with a number of light scuffs and dents. 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.