Short barrel lengths?

[lazyengineer]

The Grendel shines in the shorter configurations. It's a little casing, so doesn't hold much powder and doesn't have a lot of volume to run a sustained pressure reservoir of gas. Meaning it's gonna tap out faster than something like Creedmoor, where 63,000 PSI in that big volume casing is a lot of gas to push and keep pushing the bullet down a long barrel. Longer is still "better", but not as much so as a larger volume casing that runs higher pressure is going to do for you.

So in just a 12", that sucker is 1000 ft-lb out to nearly 300 yards. That's game-dropping power. 800 ft-lb past 400 yards, which is also game-dropping, though more on the large-varmint sized level. It's supersonic out to 900 yards, meaning it's still accurate on paper out to .. well, probably 800 yards, before transonic stuff starts to happen. Out of a 12" BBL. Cross reference that with even a 16" .223 rifle, and it's jaw-dropping how much more effective Grendel is.

Just MHO, but running a 22" Grendel misses the entire point. The point of Grendel is the most ass you can fit into a small framed AR. And to capitalize on that - run a small AR. I personally think the 12" BBL "Pistol" is about to go away and wouldn't advise anyone start there in 2021. Which leaves sticking with a 14.5 pin and weld; which you can legally run as a rifle.

Just my opinion.