- Adjustable Ranging Telescope
Developed and patented by
James M. Leatherwood, the Adjustable Ranging Telescope (ART) system combines a rangefinding scale inside the telescopic sight(scope) with an adjustable cambuilt into the scope's mount that raises or lowers the rear of the sight to compensate for the trajectoryof the bullet. The cam is preset for a specific cartridge; i.e. the 7.62 mm NATOround. In use, the shooter first estimates the rangeutilizing the scale or scales visible through the scope, then adjusts the cam to that specific range. This then allows the shooter to place the scope's aiming point directly on the target without having to hold over or under to compensate for the bullet's rise and fall.
As a brief history; during the
Vietnam Warthe U.S. Armyfound that they desperately needed snipers. They were losing troops to enemy snipers and had no capability of retaliating in kind. Their major problem was that the classic training of a sniperin rangeestimation, ballistics, compensation for weatheror climatevariables, and precision shooting is a lengthy process and they didn't have the time. About this time, LieutenantLeatherwood, who already had the patents for his ART system, entered the Army and began working with U.S. Army Ordnance [http://www.goordnance.apg.army.mil/Default.htm] specialists. The combination of the Leatherwood ART with M14 National Match rifles to produce what became the M21 Sniper Rifle, allowed the Army to place competent snipers in the field with all line units.
Modern "civilian" versions of this system are sold by Leatherwood Optics [http://www.leatherwoodoptics.com/] and a more detailed Manual of the scope and its mounting system are available there.
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