The Grendel is a long range bullet that can use A-max projectiles that shoot as far as the creedmoor 6.5 and the 260rem.
There used to be a Grendel dedicated forum online. Haven't been there in a couple of years though.
The military was making all kind of noise about replacing the .223 with the Grendel and then they dropped the idea which is a shame
because anything the military shoots seems to be cheaper since everybody starts making it.