If you can get one.....
Cimrad by Kigre systems. It's used by many, many of the elite & for good reason. Facial recognition at distance is easily achieved, unlike many of the others that are better marketed, & less capable.
It's simple & adaptable. The top 1/2 of the front ring is replaced by one that has a horizontal slot with rails milled in - it is left in place. An adapter ring screws in the front objective to replace, or in lieu of, the sunshade.
The system itself slides in the front objective & onto the rail. A simple lever cams the whole device down onto the rail & that's it!
Total time to go from day to night is about 10 seconds. Since it reflects the image from above it doesn't need to be re-zeroed (other than a standard 3.5MOA down click to adjust for the optical height) it does NOT need a dedicated night rifle to be hooked onto. It can be switched between rifles without need for zero change too.