The wider bullets also slow down more quickly, though.
Not to get too far into the weeds, but focusing on muzzle energy specifically is sort of missing the point of these cartridges, and Grendel in particular. The purpose is a round with a higher BC than the 223 typically has, so as to retain more juice down range and ultimately shoot flatter/straighter out to 500yd and beyond.
Also, the bolt thrust issue isn't a Grendel-specific issue. Any time you try to get much more power than 223 out of the AR parts, it seems like stuff starts letting go...almost like the rifle('s designer) is trying to tell us something
So accepting that a certain general power output is to be expected at the muzzle from an intermediate-sized rifle (let's not kid ourselves, none of these hot-shot cartridges are hugely different than the base chambering since there's only so much powder volume to play the game with. Want to see the game change, see the AR10), the best thing you can do to make it more effective farther away is to use higher-BC bullets that don't slow down as fast or drift in the wind as much. Grendel won't hit as hard as 308 or reach out quite as far, but it gets lead on target nearly as far despite being much lighter/weaker to start. If the extra energy truly is required out there to punch through stuff tougher than jelly, see again the AR10 (or M240/etc)
Go much smaller than 6.5mm (223) and it's increasingly hard to get high BC bullets stabilized as they become veritable needles (with attendant terminal performance & bullet construction difficulties); go much wider and you either slow way down with heavy bullets (500Beowulf) or greatly limit your range due to diminished BC (300BO supersonic). All these regimes are plenty useful, but straying from long-ogive 6mm size rounds moves more towards specialization than generalization. You won't get as dramatic of high velocity effects as with 223, nor will you get the inertia & penetration of a big bore thumper, but you will be able to engage targets with reasonable effect to much greater distances than with the other regimes. For a rifle intended for war or hunting, I have to agree with the analysts of old that long-range performance is typically something to be compromised on for superior effect closer in, since target shooting is rarely real life.
But for those who naturally want a single gun that 'does everything,' the Grendel and similar cartridges seem to be a happy median between mass(meat penetration), velocity(barrier penetration), and range(target shooting). It can do practically all the same jobs as both the fast and heavy chamberings (including some which are mutually exclusive like armor penetration), but can also reach out further than either group. It basically adds a whole other dimension (mid-long range) while sacrificing very little otherwise. A pity Alexander's company was so stingy with the rights, or it probably would have dominated early on during the AR wildcatting craze, potentially sucking the oxygen away from Blackout.
TCB
