Installation of a mortar on a rough surface is not possible. The mortar is established. But the shot sets it in motion by air.
It works also at an equal porerkhnost. Successfully to make a volley a mortar as game in a roulette, can it will turn out not always. All stationary weapon has to be installed horizontally, on any surface of the earth, on any not equal surface. Conditionally, you will always prepare an equipment installation site in horizontal situation. It has to work as are established on not an equal surface the building, and to have a steady binding to the earth.