Improvising with the 4.2-Inch Mortar
Some years ago the tail fins were falling off 4.2-in mortar bombs after they left the tube. Some boffin came up with a new system of spot welding them and School of Artillery was given the task of trialling the modification. We dug a gun pit for the mortar in Paradise Valley, with a slit trench behind for the crew for protection from possible flying fins.
How do you drop a bomb into the tube and get back safely into the slit trench? Brian O'Connor came up with the 'piece of No.8 wire'. The extractors of a 3.7-in mountain howitzer were fixed on the muzzle of the mortar, and the 4.2-inch bomb was lowered gently onto them. A length of sash cord was attached to the extractors forward through a pulley anchored in front and then back to the slit trench where the No.1 would gently pull the sash cord. The extractors would be pulled away and the bomb would drop down the tube; off it would go into the blue. Everyone was quite safely because the crew was tucked up nicely in the slit trench. At this stage I would venture to point out that everyone was School of Artillery staff (quite senior), and there was a pair of ammo techs.
Well there were no problems, so after a while we all stood up around the slit trench to watch the festivities until the inevitable happened, and the bloody extractors stuck. By this time the baseplate had gone a fair way into the ground and the muzzle was poking only about 6 inches out of the cradle which in normal circumstances was quite stable. The problem could have been fixed by going forward and freeing the extractors, but this was too simple. It was more interesting to YANK the sash cord...
A burly gunner YANKED (in capitals because I mean YANK) on a sash cord
tied to a jammed set of extractors. The whole thing become unstable and
the extractors disengaged from the tube - and the bomb. The tube fell to
the left and let the bomb do what mortar bombs are supposed to do.
By the time the bomb left the muzzle, instead of pointing up Paradise
Valley, it was pointing sort of in the area of the OP which was up the
Burma Track, manned by Bruce Murphy and Les Auty. Alan Boyd called up the
OP and it went a bit like this:
26 for 25 duck over
God knows where it landed but we heard it and it was way north of us. The Chief Instructor, when he heard about it was not amused, I can tell you.