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Seems to me it is more a stubby rifle but with a pistol grip in the common AR 5.56 platform.
https://www.ruger.com/products/ar556Pistol/models.html"
The thing that looks like a butt stock is an "arm brace" with a strap that goes around the arm. In my opinion, it's a very unwieldy, heavy pistol with a barrel that's too short for commonly used 5.56 ammunition and too long for a pistol. A real pistol is more useful. But to each, his own. Many young folks think they're really cool...er, "sick," or something. It's all commando looking and stuff.
As explained in an earlier post, an AR pistol is a way around having to pay the $200 tax for an SBR. A good stock is much better, but a brace makes the AR pistol a very effective close in system. And the velocity of a .223 round compared to a pistol caliber round makes it much more deadly. So its not just ‘sick’ looks.