Did I stutter

i would like to see the damage this does to the shooter

If my math is right. A 2 gauge would be about 7.5 cm diameter bore. So basically the Sherman main gun.
But I am bad at math so someone please check.

So a Punt gun, a pump action one but still a Punt gun. Btw, those are illegal just about everywhere. https://en.wikipedia.org/wiki/Punt_gun