The last two (111 and 11) I swapped out, I just changed out the rings to Burris Signature Z rings keeping the existing weaver mounts.

Nothing wrong with the weaver bases. As pointed out above... Check to make sure they installed and torqued correctly. I pop them loose, and re-torque them after putting a little loctite blue 242 on the threads. Never had one come loose using that, but lets you pop them loose if you need to take them off..