The primary reason the AM was designed, was to add an anti-tank capability to 'Nouveaux font' casemates and ouvrages, many of which were only equipped with light-calibre weapons in cupolas. The system was mounted in an AM cupola, some converted 75mm turrets and turrets together with a 50mm mortar.
|¹ When mounted in a cloche
² When mounted in a retractable turret
|Total weight||199 kg¹
|Armour penetration||30mm/30degrees° ¹
|Rate of fire||30 rounds/min|
Needless to say, a gaping hole in an embrasure presented a perfect opportunity for an attacker to fire upon the crew inside the casemate as the JM and AT gun were exchanged.
Because the weapon was used in several types of configurations (e.g., cupolas or turrets), several versions existed. The main difference was the length of the barrel.
The sectors in which the AM were employed were Escaut, Maubeuge, Montmédy, La Sarre, and Rohrbach.
Eleven JM cloches in SF Escaut, Maubeuge and Faulquemont underwent a complicated, labour intensive, and costly upgrade to receive this weapon.