Since this thread got resurrected,,here goes...
I played with the ARX-100 at SHOT 2015. They had a few barrel lengths up on display. On first impressions, the gun looked good. Picking it up, felt like a cheaply made Nerf gun. The controls are tiny and not particularly ergonomic. Most of it is plastic. The only thing going for it is that it is very light. A mid range AR would run circles around this rifle. A couple of guys picked up the rifle after me, cycled the action, shrugged their shoulders and went on their way. Not much to say.