During my time in the Belgian army in Soest, I was part of the 6th artillery batallion, which used as its weapon of choice the 105 mm Howitzer. I had to look this up in Wikipedia, this must have been the M108, which is (maybe unsurprisingly) American in origin, and had been withdrawn by them by the time I was doing my military service. I see that Wikipedia also states that they were more suited for holding defensive positions rather than act as mobile artillery.
Now how things worked was that a team of surveyors gave us in the shooting office the coordinates of both our artillery pieces and the targets of enemy positions. We then performed the calculations using some standard paper-based method to convert these coordinates into elevation and direction of the central piece in a line of artillery pieces. The calculations also took into account whether you wanted the shell to explode on the ground or in the air (the latter for illuminating the battle field at night), and the elevation had to be adjusted accordingly.
As I’ve already mentioned before, warfare had already moved on by the early 1980s, and it was clear from firsthand experience that this type of artillery would be sitting ducks against both long range artillery and far more mobile attack helicopters. Besides, when we had to go on exercises, the artillery pieces had to be transported on trailers, limiting their excessive diesel consumption to moving them around on site. I later heard that ours was the last exercises who took these artillery pieces into the field.
The Howitzers we had could in theory fire a variety of shells, from the standard ones to flares, white phosphorus incendiary and last but not least nuclear ones. For the latter we would have to go to an American base, collect the tactical nuclear ammunition (about the same strength as the bomb dropped on Hiroshima) and fire them using calculations specific to this type of shell. The joke was that whatever the instructions you would fire them as far as possible, because even the maximum range of 14 km would be uncomfortably close for a nuclear explosion.
I’ve only seen the use of two types of shell, the standard one and the incendiary one. I only became aware of the latter because during one of our exercises, one of the white phosphorus shells was misdirected and fell into civilian territory. The fact that only one out of six shells did so cleared us from any blame, since if it had been the calculations which had gone wrong, then all artillery pieces would have pointing in the wrong direction. I wonder whether it was anybody’s job to notice that one artillery piece did not point in the same direction as the others.
At the time I thought the use of outmoded Howitzers proved the pointlessness of the Belgian army, but maybe I was being too harsh, and maybe there were plans to replace them with something that fitted in better with the requirements of the day. Just maybe.