Talk about a mag dump. They loaded it up with 6 100 round Beta C mags and dumped them as fast as they could. That is a lot of trigger pulls. Finger must be getting a helluva' workout. Ok, to note, this is just the lower reciever, or the actual part of the AR-15 that is considered the "Firearm." All the lower reciver does is hold the trigger and hammer assembly, has the magwell, and attaches to the buffer tube. Things like the safety, the mag release, the pistol grip. It's just a hunk of aluminum (or plastic in this case) that holds that stuff. The Upper is where all the important guts are, like the bolt assembly, the chamber, the barrel, etc... This is pretty cool. It's plastic, and I would not put a whole lot of trust in it. But It's cool nonetheless.