I have a Leica 1600-B that is not calibrated correctly. Was at the range today again, at the 200 target I ranged 183 yds. At 500 yds it read 459 yds. At the 1000 yd target it read 939 if I remember correctly. Anyone had a similar experience? How can this be corrected, or can it be corrected? I became suspicious when I shot with a friend and we both ranged the same target and came up with very different readings. I purchased it new several years ago so I am the only owner.