Re: 300 RUM for starters
RE: Scope recommendations.
I think a lot would depend on your personal preference such as hold over/under or click.
If hold over/under than an appropriate, personally comfortable reticle would be in order.
If clicking scope options open considerably with decisions on turret design needed. That is, MOA/IPHY clicks or Drop Compensation clicks. This consideration has more to do with setup up time i.e., BDC turrets may be less complicated. Thus quicker and made with more confidence (the first time) than with MOA or IPHY clicks.
With big game time from spotting to taking the shot may be minutes or longer. For predators the time is usually measured in seconds and not very many of them.
Most here will recommend the Night Force but there are a lot of options out there. Depending...........