Brit 3 inch mortar in Burma - btw the photo has been reversed, the no.2 normally stands on the other side of the weapon and drops the bomb in - he has to do this as the sights are on the other side and he has to set the elevation bubble.
The no.3 prepares the bomb and sets up the tripod, no 1 rides the baseplate when shooting in and set the sights to be level and on the aiming post.
Funny the stuff you remember from a course 20 years ago...
