600 yards? Heck, I can't even SEE that far.
From the little I've studied it, the Grendel seems like it would be a dandy deer/antelope cartridge out to at least 300 yards, which is about 150 yards farther than MOST people should be attempting to shoot at them.
I'm just put off by the rather stiff price tag of one of the Grendel upper assy's...