Hello all, I just aquired what I believe to be an original Vietnam era Leatherwood ART/MPC scope. Other than the graduations, the only markings of ANY kind are the letters "ART / MPC" on the left side, and serial number 00XXXX on the left side of the elevation turret. It is graduated to 600 meters. However I know little about it. I've gleaned a rough understanding of it's adjustments and setting process from the website,(http://www.leatherwoodoptics.com) but was wondering if anyone has has any experience with this scope or something similar, as they don't list this model or it's manual. And it does differ in some ways from the newer Leatherwoods. Anything you can tell me would be greatly appreciated. Thank you.