In early 1962 the David White Company Realist Riflescope Division developed the Realist 3X20 20mm objective Ballistic Drop Compensating cam (BDC 100-400 yards) telescopic sight for the Armalite AR-15/M-16 rifle.
Manufactured by Realist under a "private label brand" contract with Colt Industries, the 3x20 scope was marketed as the Colt AR-15 sporter rifle scope for their AR-15 5.56 rifle and later also under a "private label brand" contract with Fairchild-ArmaLite the 3x20 scope was marketed as the Military Weapon System for their AR-18 5.56 selective fire battle rifle.
The BDC capability for the 3x20 scope mounted on the M-16 battle rifle enabled the rifle to effectively server as a light squad sniper rifle at combat ranges up to 400 yards.
As the intensity of the Vietnam war expanded in 1968, Colt Industries purchased from Realist the patent rights of the 3x20 scope with Colt entering into an exclusive manufacturing contract with Japanese optical company TASCO on a much larger scale than the capacity of Realist.
Realist is estimated to have manufactured less than 900 non-serialized 3x20 scopes from 1965-1968 (marked on top of the scope tube "COLT MADE IN USA") while TASCO manufactured in excess of 12,000 scope from 1968-1973 (marked on top of the scope tube "COLT MADE IN JAPAN"). The Realist scope were primarily issued to U.S. Special Forces, USMC Force Recon and MACV-SOG units while the TASCO scopes were primarily issued to the U.S. Army 1st Cavalry Division.
The external appearance of the Realist made and TASCO made scopes are almost identical. The Realist scope reticle was a conventional heavy crosshair, while the TASCO scope featured either a duplex reticle or an inverted post crosshair reticle.
See “The Long Range War” by Peter Senich pages 126-138.
This unit was issued to MACV-SOG in 1967 and features a very rare two mount system for both M-16 and M-14 rifles. The M-14 mount attaches to the M-14 receiver using a stripper clip replacement fixture (not pictured).