One would think that mortars are a lot less susceptible to recoil effects than their longer barreled cousins. A mortar’s projectile doesn’t spend much time under the influence of “interior ballistics”, given a mortar's very short barrel.
Here are some pictures of my sleigh carriage beer can mortar. The first shot is taken the moment before firing. Note the position of the carriageÂ’s base relative to the ground.
The next shot shows the moment of firing. The can is still somewhere in the fireball having just emerged from the barrel. Note how the rear of the carriage has squatted down into the dirt, appearing to cant the barrelÂ’s elevation slightly upwards.
Here is the next frame, 0.067 seconds latter. The can is now visible towards the top of the frame, already tumbling:
I hope to repeat this shot sequence with my new digital camera. It will record 640x320 fine resolution movies at 30 frames a second, twice as fast as my current camera. I might get lucky and capture the can just as it is exiting the muzzle and see how much the carriage base has moved.
As a side note, my heavier coehern mortar simply slides straight back on its flat base and doesnÂ’t seem to significantly alter itÂ’s elevation at the moment of firing like the sleigh carriage mortar.