I have three AR pistols in 5.56 / 9mm / 308 - And never used a brace. I actually prefer the single point sling setup.
And yeah - A loud as hell 308 pistol.
Why? If you can't answer that - Go paint your toes... :)
The trick would be to build adjustable platforms so all their faces line up.
Head shot. 750gr 50bmg.
I bet it breezes through a 100 of them before it goes subsonic...
When I moved from khalifornistan - I sold about 20k rounds of ammo.
One of my Sheriff buddies came over one day laughing his ass off - Since one of my leftist neighbors called in a "suspicious drug dealing" complaint...