Rell:
AHR does outstanding work (as I know), but I would re-think your choice of scope.
On my 300 H&H, I'm switching to a 30mm Leupy 2-7x w/ illuminated reticle.

Anything beyond a 2-7x for a 300 magnum rifle dedicated to big game is just going to create more length, weight & eye-relief issues, or give way more magnification, than you're going to need inside 500yds - the so-called "Rifleman's Quarter Mile" (in America anyway.)

From my own hunting experience, I'd anticipate shots on game, realistically, to be inside 300yds for sure, and more likely inside 200yds.
The 7x max (with illumination) will give plenty of magnification, and max-ing out to 12x would only make the shot harder, not easier.

I'm sure others will differ on scope choice, so for what it's worth this is my opinion.

Otherwise, it sounds like you're getting another great AHR rifle.