I changed out of set of rings yesterday on my Savage 110 FCP-K in .300 Win. Mag. I went from 1" Burris Signature Zee Rings which I've had excellent luck with, to a set of Leupold Mark IV Medium Height Steel Rings. The reason I changed was not because of scope movement or zero shift, but because the 1" Burris Signature Zee Rings only have 1 mounting screw per side for each top ring half, 2 total per ring.
What happens is because of the way the radiused inserts ride and self center in the mating radius of the ring itself, it allows the ring cap to rock or gimbal because of it only having 1 screw. This can be seen when looking at the gap between the ring cap and the lower half of the ring itself.
After about 60 rounds of full power .300 Magnum loads the gap was all but non existent on the front half of the ring, and wide open on the back half, as the top ring half gimbaled forward. The scope itself did not move in relationship to the ring, and zero held dead on. I felt this type of lateral movement was stressing the ring cap screws too much, so I elected to replace them before something detrimental did occur. The 30 MM Burris Signature Zee Rings come with 4 screws per ring, and this would be a better option for the 1" rings as well.
Anyway, on to the Leupolds. After removal of the rings from the Burris steel bases, I installed the Leupolds, (Midway has them on sale for $124.00), and began the lapping process using a 2' brass lapping bar I "appropriated" from work. Using fine compound I lapped until I had a nice full, half round pattern. When I lapped the ring caps I simply held them with my fingers and lapped them independently until I had the same half round pattern.
After that I cleaned everything with Kerosene and alcohol, applied rosin to both ring halves, set the scope and torqued everything. I've heard that some will lap the ring caps attached. I can't see doing this because it won't allow the lapping bar to pass freely. Also, I see zero advantage to it. The top ring halves free float to the scope anyway because of the clearance in the screw holes themselves. Do you guys lap with the top ring half attached, or do you lap them separate? Everything went well with this installation, and I'm hoping to get the rig to the range next week. They're predicting rain today and tomorrow, and I work weekends.
[img width=600 height=450]http://img18.imageshack.us/img18/7748/leupoldmarkivtacticalri.jpg[/img]
Hopefully this will provide a little more rigidity. Braked Magnums really stress out ring and mount hardware. You wouldn't think so with the reduction in felt recoil. Bill T.
