Just had my Garand out to the range for the first time and it worked beautifully! I have one question though- my sight is way out of whack. Is there a standard number of clicks from the bottomed out position up to the 100 yard mark that I can reset the elevation knob to? If not how do I get the sight zeroed? Also, after the 800yd mark, there's a R Z F on the dial followed by 1000yd and then the letter M. What do the letters mean?