At a guess I'd say it was a heavily customised AR-15 (or AR-15 copy) because the aftermarket parts industry for AR-15s is fucking mindboggling and leans heavily towards tacticool.I looked at the thing again, Christ for all we know its something he Frankenstiened together out of drastically different looking but mechanically compatible parts to fit his definition of cool. Either way, its at the least a semi automatic rifle, with a magazine capacity between 20 and 30.