I have a 300 RUM (lovingly referred to as the Elkinator). It is a fine cartridge. Just remember it is a sports car. It guzzles gas (like 1 lb. powder per fifty rounds!), and burns out tires (throats).
I still love it for the raw horsepower.
For glass, Leupold, Swarovski, and Nightforce all make fine scopes. I currently own some Leupolds, a Swarovski, and several Vortex riflescopes. I have really come to like Vortex lately, but the scope with the best image is my Swaro Z3. I had my 4-12X50 on my 300 RUM, and it was a great combo. I know the Christensons run the same scope on theirs.
I have used many Nightforce scopes, and found them to be spot on accurate in their adjustments. They are also super-durable. They are optically pretty good, but I think someof the competition at their price point is better.
If you wouldn't mind the weight of the Nightforce, you should really look at the SWFA SS 5-20X50 HD. It has just as good of adjustment reliablility, more elevation adjustment, better glass, a FFP reticle, and costs a little less.
Another great premium scope is Premier Heritage.
For a lighter weight scope with top-o-the-line glass it is hard to beat Swaro or Zeiss.
Sightron's S3 series is a tremendous value with great adjustment accuracy.
Lots of good options.
