I mounted that same scope on my .30-'06 Ruger Express, and a similar-sized one on my 338 Win Mag Ruger Express (never scoped my 375 H&H, but the rib is going to cause the same problem for all of these rifles). Because of the rib I had to use the "medium" Ruger factory ring set (their #4 front and #5 rear), where without the rib I would have been able to get away with the "low" set (their #3 front and #4 rear).

According to the Ruger ring chart in the Brownell's catalog, the distance from bottom of ring to top of base (in this case, top of the Ruger receiver) is 0.435 inches for the #4 (front) and 0.565 inches for the #5 (rear).

Also according to the Brownell's catalog, the distance for Warne's "Ruger base QD" sets are 0.410 inches for the "medium" and 0.535 inches for the "high".

It doesn't appear that the Warne rings are "paired", with different heights, like the Rugers are. Seems to me this could potentially cause some problems on a heavy-recoiling rifle.

A few years ago when I inquired about QD ring options for the M77 I was told that the Warnes were nicely made but they didn't quite fit right. Until tonight I thought that was an issue about how the ring fit to the receiver, but after going through this exercise and collecting the various measurements I wonder if the problem I was told about was caused by the use of a single ring-to-receiver dimension.

Why not just carry a tool to remove the factory Ruger rings? That would be far less expensive, and spare the risk of damaging a scope...or yourself if the mounts turned loose under the recoil of the Lott.