Frontal fire was possible but limited (especially for the first generation of casemates) but the ability to do so was expanded later by means of specialized cupolas (a JM or sometimes, at New Fronts casmates, an AM or upgraded JM). The former was often embedded in concrete to make them less vulnerable to enemy artillery.
It was the task of the neighbouring PO’s and GO’s with their heavier firepower to clear the areas in front or even on top of the interval casemates. The casemates were strong enough to withstand impacts from neighbouring ouvrage artillery pieces. Let’s not forget that the artillery batteries of the Army units and infantry troops were also supposed to play a key role in their defence. After all, the Maginot line was a defensive system, in which various elements of the army played a key role. Unfortunately, because of the dramatic events in 1940, this system could very often not work properly.
In general, a CORF interval casemate had two main armoured firing embrasures per firing chamber (and sometimes a third one for close-in defence). One for a twin machine gun (jumelage de mitrailleuses or JM Reibel) and one that could be used for either a second JM or for a 37mm or 47mm anti-tank gun. On the next page a look at the machinegun position indicated on the image below as nr. 1. By the way, the 50mm mortar position depicted below is unique. This is the CORF interval casemate Font d'Havange.