Turning live rounds into empty cases.

#4
So - here's a system that helps you run out of ammunition faster? Or that means you have to carry three times the weight of ammo? And won't barrels overheat with that sort rate of fire?
 
#6
Not really sure what the 'Beruit unload' in the video is supposed to prove. How fast you can miss the target, whilst melting your gas tube and/or burning out the barrel?

To my mind these big box magazines are a solution looking for a problem. We are better off with the new E-Mags and if more full auto fire is wanted, the answer is likely to be belt fed.