Well I have a 10 22 with the factory barrel still on it. I figured that I would fire some 25yd and 50yd groups to see how the factory barrel does before my GM arrives. The scope mount is a T0-9 with Leopold high rings, the scope is a Busnell Banner 6-18-50mm. I tried to zero the scope and ran out of adjustment. Bullet impact is 3-4 inches low. I took all the mounts off reversed the rings and base but the bullet impact is still the same. I am worried that I will have the same results when I change my barrel. Any ideas on what I should do? I have other scopes but I am thinking I will run into the same problems. I thought that it was the base but after reversing it and changing the mounting location i still have the same problem.    

I've had that on a couple of my rifles. I centered the recticle and use shims made from an aluminum can between the rings and scope. Fixed the problem. You might try reversing the mount also.

I have reversed the mount the rings, I have to lower the scope but I have a limited number of options. The scope is only going to clear the barrel by 1/8 of an inch. Is it a good idea to only put shims under the back of the scope to move the reticle down? Would this cause the front mount to clamp the scope at an angle?, possibly causing damage to the scope? Thanks I did try one piece of paper it moved the impact about a ¼ of an inch.

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Remove the scope mount and put a straight edge on the top of the reciever. It may have a hump on it. Dont' shim the rings themselves as this will damage the scope. Shim under the back of the base if you have to shim anywhere. This will keep the rings aligned while raising the the point of aim. You may be able to have the top of the reciever milled to fix it if this is the problem.

Here is an update, i was thinking of milling the base a bit to give it a slope but then relized the reciever and the base have a slight curve to them. The only option I can think of is to shim the rear of the base. maybe need .02 of an inch? Bullet impact is 3" low at 50 yards with the scope adjusted all the way. Woould like to put the scope back twards center of adjustment. Will have to shim and see.