Actually the M24A3 IS chambered in .338LM rather than 7.62x51. But, as stated, it's a serious powder hog. OTOH, any of the big Magnums are, so it's not really much factor. Going that route would be easier to get initial ranging data for since the US Army already has all the range data established. It all comes down to what a guy wants to spend.
If money weren't a problem, I'd go with a McMillan. The only problem is that while they finally chamber in .416 Barrett, it's still only offered as a single-shot. When they provide it with a detachable box mag it will be the perfect extreme range platform. .50BMG is awesome, but the .416 is still a step up in performance, and McMillan is more than a step above Barrett. So it's nearly a perfect marriage with the Tac-416. Come on, Lottery!
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