Originally manufactured by Unertl Optic Company as a 10x USMC 7.62x51 mm NATO calibrated optic, this scope is one of a limited number converted for the Marine Corps to .50 BMG calibration for use with M82A1/M107 semi-automatic sniper/anti material rifles. The left side of the adjustment body is marked "USMC" over the serial number "1301", with the original ".30 CAL" marking milled away and replaced with ".50 CAL". As a part of the conversion, the elevation knob was replaced by Unertl with a .50 BMG calibrated knob graduated from 100 to 1,800 yards. Fitted with a pair of "GGG" marked scope rings. Includes a matching Civilian Marksmanship Program (CMP) Certificate of Authenticity dated February 19, 2021.

Very fine overall as converted to .50 BMG by Unertl, issued by the U.S. Marine corps, and subsequently surplussed through the CMP, retaining 89% plus black finish with light edge wear, scrapes focused on the windage knob top, clear adjustment markings, minor handling marks, and minor oxidation to the reapplied caliber marking. Optics are clear with crisp reticle.