My last post on the subject of mortars and using your body as a baseplate.
Here is a picture of a 51mm in use. Attached is a blowup of the base of the barrel.
Please note - the baseplate is underground.
This is normal when firing a 51mm Mortar. The ground looks very hard.
You look for firm ground when siting a 51mm Mortar.
This characturistic of mortars follows Newton's 3rd law "For every reaction there is an equal and opposite reaction". In this case the force required to launch a mortar round from the barrel and to the top of its trajectory must be dissipated through the baseplate. There is no buffering of the 'recoil', and the kinetic energy produced
far exceeds that of a 30mm grenade being launched from a M203 or rifle propelled grenade.
So there you have photgraphic evidence of my point.