Shortly after Jim Leatherwood introduced the scope (1982 time frame) I purchased a civilian model ART/MPC 3 X 9 scope and No. 505 FN/FAL base. It was mounted, and remains so, on a competition grade .308 (7.62mm) cal. FN/FAL LAR 50.00 rifle. Using the cam that was installed on the scope as purchased, the scope was calibrated and zeroed on a range for the NATO Standard 7.62 X 51mm M80 round (147 grain bullet). Suffices to say, the weapon is extremely accurate to 600 m. My question to the forum is where can I find any information on the alternate caliber trajectory cams (marked A,C,D, with B presumably on the scope), which came with the scope. Any one familiar with the original documentation which accompanied the scope, knows it’s a bit “rough”, and I can’t remember, if I ever knew, the purpose/operation of these alternate cams. Each is marked with a different set of spaced numerical calibrations, i.e., 2 - 6. Would sincerely appreciate any additional knowledge, with my thanks in advance.

Arnhem Jim
Arizona Territory