First off you are overgunned for the stated ranges as a 30.06 will do fine. Now at 1500 you are getting up to speed which is one of the intended effective ranges Bob McCoy (Ballistic Research Lab, APG)designed the round for when I was there and he briefed me on it as it was getting finalized.
Your problem is identifying a scope with repeatability.
Here is how to check to see if your internal adjustment scope repeats.
Fire a five shot group at 300 yards, crank up 20 clicks, right 20 clicks, down 20 clicks, left 20 clicks and up 20 clicks and see if the next round goes in the five shot group.
Continue this exercise in all four quadrants and if you don't see a increase in group size you have just received your Christmas present. If it doesn't repeat then you know you are among friends here haha. Very few internal adjustment scopes will pass the above four quadrant test.
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