Burris Tactical Rings have 6 screws and will hold zero. The Burris Signature Rings (with the plastic inserts) in 30mm have 4 screws each and hold zero but I would not trust the old windage mounts with two screws per ring as far as I can throw them. When the Burris Signature rings came out, an outdoor writer went on a muskox hunt in the NW Territories. After his plane landed he went over 100 miles on snowmobile. There were 6 guests hunting with him. The bouncing snowmobile destroyed the zero of every scope in camp except his. I have enough experience to know that by using different fillers in the plastic you can get the abrasive grip level you want on the plastic inserts. They seem smooth to us but grip under pressure perfectly. I am limited to the old windage design on my two B-78 Highwalls and suffer constant shifts. Remember that we would all use ancient windage mounts if they held. Burris and Leupold both came up with additional ring designs because they do not.