I mounted a Leupold Mark 4, 1.5 - 8 X with an SPR reticle on my M1A Bush Rifle (18 inch barrel). I used an ARMS # 18 mount and a set of ARMS # 22 low rings. I attempted to zero the rifle/ scope at 25 yards. During the proccess I found that I was shooting very high, about 20 inches high so I adjusted the elevation on the scope that brought the rounds down a couple of inches but I ran out of adjustment on the scope. So even with the scope adjustment bottomed out my rounds still hit about 15 inches hight at 25 yards! What do you guys think?