Originally Posted by
Jim Tarleton
I had the pleasure of mounting a M8 on my A4 about a year ago. The first thing I did was center the crosshairs (same number of turns either direction, windage and elevation). Don't touch them again until you start shooting for fine tuning. I had received some shims from someone on this forum (thanks again) that were absolutely necessary and saved the day.
I put the barreled action in a gun vise before I started all this with the flat of the receiver dead level. Mount the base, mount the scope, center the vertical crosshair will a plumb bob and turning the scope in the rings. Tighten the rings. Bore sight the rifle on a distant object (100 yards if possible). Using the rear mount adjustment screws, align the vertical crosshair on the distant object (after bore sighting). You will see that the horizontal crosshair winds up below the center of the object. Add a shim under the front of the base. You have to remove the scope from the base to do this, but only loosen the right side windage screw and don't move the left windage screw on the base. Remove the base and add the shim(s). Put everything back together and see if the horizontal crosshair has moved closer to the center of the distant object.
If both crosshairs are centered, you are finished. If the horizontal crosshair is still not centered, add or remove shims as needed, repeating the above process. You want those crosshairs as close to centered as possible, as the Weaver scopes of that period don't have a lot of adjustment in them (8 to 10 clicks each way if I remember correctly). You will need that adjustment for fine tuning once you start live firing.
It sounds like a pain, and it is, but once done, they pretty much stay where they should. I click on my scope is 1 MOA. I was so used to 1/4 MOA adjustments, that I blew a lot of shots for nothing.
I also used a bore sighter, which made the job a lot easier. If you can get your hands on one, use it!
I don't like those scopes. 2.5 power sucks in my book, and light gathering is way bad. Still, it shoots where it is pointed and that scope did the job for many years.
Good luck.
Jim