Right, range doesn't matter. The point was, however, that the BMG delivers as much, if not more energy at the muzzle, and, on top of that, has the enviable ability to retain that energy at longer distances....
Given the choice of two weapons, the one that delivers 6 tons of stopping power at the muzzle, verses one that delivers the same six tons, but reliquinshes that energy at a slower rate(and is thus to put that same charging elephant down at greater ranges--if necessary), not to mention is less taxing on the shoulder, why bother with the .700 artillery piece?