Does the 6.5 grendel have the potential to replace the 5.56 for the military?

[stanc]

I've always wanted a 6.5mm LMG, and it looks like LSAT will deliver that in a 12lb package, with ammo that weighs less than 5.56 linked.

Yes it does. But, the squad automatic weapon and the individual weapon have always been the same caliber. It's a safe bet that if a 6.5mm CTA LMG is fielded, a carbine that fires the same ammo will also be adopted.

So, in the event that cased-telescoped technology does not pan out, I just don't see a Grendel LMG entering service without the carbine also being 6.5 G, despite the drawbacks you've noted.