I rather suspect the guy firing it doesn't have Lace. And given the size of the damn thing I'd say firing offhand would be about impossible, and hip-fire is never very accurate over about 10-15m.(plus a Muscle and Bone Lace enhancement to avoid being crushed by the recoil).
That 20mm is impressive.
The rifle running the AR lower... wtf. It looks like something Rob Liefeld drew. And that's not a compliment. =p
Also: why are there so many rifles running off the AR lower, instead of running off, say, a Kalashnikov base?
because the AR is "modular", owing to the fact that the receiver splits in half. way back in the day, some bureaucrat decided to put the serial number on the lower part of the receiver, thus making the lower a "gun" and the upper receiver just another accessory. why does this matter? well, not a lot really happens in the lower receiver. you've got the magazine release, trigger assembly, selector, etc. the upper is where the bolt lives, where rounds are chambered, and the part that receives the bulk of the forces from ignition... after the barrel, of course. so you can take your AR lower and slap an upper on it to shoot 9mm, or 7.62x39, or 300 blackout, or 458 socom... essentially any round that will pass through the magazine well... plus a few that won't.Also: why are there so many rifles running off the AR lower, instead of running off, say, a Kalashnikov base?