The 75 mm gun model 1932 was the successor of the less succesful model 1929. The barrel had been shortened with 30 cm, but the most important change was the entirely new mounting. The barrel protruded only 30 cm and was protected by two armoured hatches. Since the rotating point was much more forward the mounting had a special platform for the loaders. The height of this platform changed with the elevation, so loading the gun was much easier. The cilinder on top (In fact there are two) contains a powerful spring which serves as a counter weight for the gun barrel. The construction behind the gun was designed to catch the ejected empty cartridge cases. Like all 75 mm fortress guns the model 1932 was equipped with a Nordenfelt breech, but some guns got a new sliding breech block. For more information click here.