The Swiss defenses were modified extensively after World War Two. This included also the development of new weapons, like the 15 cm turret model 1958. Technically seen this turret is a real master piece. With a range of 24 km it outranged all contemporary medium field guns. The gun could fire 25 rounds per minute, quite astonishing in those days. However strategically and economically seen the design wasn't a big success. The 70 m. deep shaft with all the technical installation was very difficult and the turret itself became vulnerable to the guided bombs already developped at those days. Eventually only two turrets were installed near the Fort de Dailly near Saint-Maurice.

The ammunition for the gun is fed through the an elevator in the shaft of the gun. The speed can be adjusted according to the target. The fire procedure is as follows:

1. An observer passes his observations the command post.
   
2. The command post takes the decisions about the ammunition, the settings and makes the calculations.
3. The crew in the underground rooms take a cartridge case from the magazines and put it on a moving belt. The number of the magazine corresponds with the charge of the cartridge case.
4. Another crew prepares the shells and puts it on the moving belt.
5. A hydraulic press unites the shell and the cartridge case.
6. An automatic fuse setter sets the fuse on direct, delay or time.
7. The ammunition is fed into the elevator to the gun.
8. The rounds are fed automatically in the gun and fired.

If necessary the gun barrel could be removed and brought to an underground work shop with a special elevator. Then the inner tube could be replaced and the gun could be brought back in position wihtin 8 hours.

There are two anecdotes about the turrets. The first happened during the construction of the turrets. A large armoured ring, weighting 28 tons, was transported vertically on a flat-bed trailer. Unfortunately in one of the sharp hairpin bent the trailer turned. After several weeks of discussions it was decided to transport the ring horizontally to the fort. However it was discovered that the ring was too large to go through the fort's gate. Using pneumatic hammers the gate was enlarged to allow the ring to enter. After the completion of the turret it was camouflaged like a small shed. However the designers had not taken the muzzle blast into account. The small shed was almost completely destroyed with the first shot. It was replaced with a similar construction, but it consisted of panels mounted flexibel.