I have not fooled with the Grendel, yet. It just wasn't a viable option back when I decided to what caliber to use for my AR projects. Shortage and expense of the raw brass was the deal breaker for me and the reason I went with the 6.8 SPC. I'll admit, the 6.8 is not a real great long range cartridge. Say 400 meters plus. However, for the purposes I have, home and yard defense, it works out really well.

A 110 gr. Hornady V-MAX @ 2650 fps will knock the socks off a 5.56 round all day long. Want proof ? Shoot a 5.56 at a hanging steel plate 8 inches in diameter at 200 meters. Pay close attention to how loud the smack of the bullet is on the plate. Also, how much dancing around the plate does when hit.

Now shoot the same plate with a 6.8 SPC. It will be very different in both sound of the smack and the movement of the plate. Those 100 gr. V-MAX's are real bad ass. Tear your freakin' arm off at best on a less than center mass shot.

Load a 95 gr Barnes TTSX @ 2825 fps and you have yourself a handy little 200 meter deer rifle.

So, ammo is more expensive than 5.56 but has more knockdown performance. Knockdown being the key word here and a factor to be considered.

Get off my lawn.