The rear mount is awfully hard to adjust to different ranges, and return to the different settings. They are terrible about developing hair line cracks, causing all manner of headache. With enough shooting the front dovetail mount will slop out the dovetail making holding a consistent zero a problem.
With that long scope about the only option for the rear mount is an MVA, depending on how far you're shooting either the silhouette mount for close range or the creedmoor mount for long range.