I have a Remington M700 KS Mountain Rifle in .22/250 with Burris XTR 2-piece bases and Burris Signature Zee rings. Scope is a new Leupold VX3 4.5-14. I'm assuming the scope is factory centered. Anyway, my first shots at 25 yards are 10 inches low! I have wound it up a heap to zero it at 100 yds, but I'm wondering should I be fitting a +/- 20MOA PosAlign offset inserts to the rings to re-center the scope, or would I be better to fit a 20MOA rail? Have yet to pull off scope to check base alignment but I presume this is where the problem is? Any advice gratefully received before I go any further with this.