For the 50th anniversary of Jim Leatherwood's legendary Automatic Ranging Trajectory (ART) scope, Hi-Lux introduces the redesigned the ART M1000-PRO. The original Auto-Ranging Telescope (ARTel) was issued to US Army and Marine Corp servicemen over 40 years ago. Since then, Hi-Lux has refined and improved the ART system's general cam to compensate the bullet drop of virtually any caliber. The ART scope's integrated mount provides external adjustment through the Trajectory cam. Selecting the proper cam setting will effectively match your rifle's trajectory curve to the curve of the trajectory cam. There are two ways to automatically compensate for trajectory when using the ART scope: 1) Framing known sized targets within the HR1 reticle 2) Dialing the Cam to a known distance To automatically range known sized targets, the shooter needs to frame the target within the reticle. In Auto/Ranging mode, adjust the cam until the known size target fits within the designated framing area. Once the target is framed, the ART scope will automatically compensate for bullet trajectory for distances of 200 - 1000 yards. This means no holdover or guesswork. There are several factors to consider when shooting long distances including trajectory, wind age, Coriolis effect, atmospheric conditions, spin drift, among several others. Using the ART scope eliminates trajectory from the equation when shooting long distances. The Cam system of the M1000-PRO ART system was invented and designed by Jim Leatherwood for military snipers in Vietnam during the late 1960s. By usually the incrementally adjustable trajectory cam, the M1000-PRO can be calibrated for virtually any center fire cartridge from.223 to.50BMG. The M1000-PRO Trajectory cam has been designed to be modular and interchangeable. Caliber specific cams will be introduced in the future.