[Fee]

Saw the design. It is basically a single shot handgun. One can easily replace the plastic barrel with a metal substitute to make the barrel last beyond 10 shots. Luty of Britain actually sold a book on how to make a 9mm smoothbore barrel machinegun that uses a single stack magazine with store brought parts/tubing and tools.

[USFRIENDINVICTORIA]

If you're referring to the one pictured above, it's actually capable of firing several shots.

It's made out of ABS plastic, which has a high enough "glass transition" temperature so that the barrel doesn't deform after just one shot. It wouldn't do well on rapid fire; but, so long as it's not over heated, it can be fired multiple times.