Despite its lumbering appearance the gun can fire projectiles at a speed of 1.5km per second, or around 3,500mph, that's almost twice the speed of a bullet.
Today it has been loaded up with a piece of of basalt rock, a bit smaller than a pea, which will be blasted at a very special gel.
The gel is made of the protein talin - or at least a version of the protein that has been refined and tweaked to give it an extraordinary ability to absorb impacts, as we are about to find out.
We are herded out of the gun room and after a quick countdown the gun operator, Luke Alesbrook, pushes the button, triggering the gun.
Back inside smoke wafts from the gun barrel as the target is removed. On inspection, the gel has been pushed around a bit but, amazingly, is still intact.
What's important is that the metal plate behind the gel is not damaged. Without the gel the basalt would have torn a chunk out of the plate.