Bottom gun is just a tricked out AR15 carbine with a
fancy flash suppressor.
If you notice the magazine, you'll see it's a
standard 5.56 PMAG.
It's a SBR or short-barreled rifle. It requires extra paperwork to have one.
Based on the setup: optics, mount, etc. the guy is pretty squared away.
Except for the Ergo pistol grip. Those things are just too damn scrawny.
...
The middle gun is a 12g Winchester 1300 Defender pump shotgun.
The top gun is a 12g Winchester SuperX2 semi-auto shotgun.