Check Out This Lego Sub-Machine Gun That Shoots Lego Bullets [VIDEO]
Using only Legos and rubber bands, Jack Streat was able to build a fully-functional replica of a Heckler & Koch UMP 45 sub machine gun.
This is far from the only time Streat has fashioned a potentially dangerous thing out of Legos; he was able to build a working chainsaw out of the construction toys, and has a Youtube channel full of videos of other Lego weapons he has assembled.
The video for the UMP 45 is below. A Lego gun doesn't quite shoot with the same velocity or distance as a real gun, but if the TSA bans Legos from flights, you know who to blame.