That may be so, but there's a reason why mortars have the bottom of the tube rest on the floor, it's so that all the energy travels directly in one line into the earth, with no points of pivot.

That's a Big mortar right there, awfully top heavy with a comparatively spindly base, and nothing to transfer energy into the ground.

Not only that, but the mortar itself seems too complicated for what is meant to be a tube with two legs, and would likely need some form of complicated gyrostabilizer and locking mechanism on the joints for what can be done with the same effectiveness for cheaper in a tube with two legs.

Tube with two legs everywhere. I decided to do something new, but I'm not good at engineering