Why?
MP40 has only full auto, but according to information I've read, the fire rate is very manageable to pull single-shots.
It's an open bolt firearm, meaning the reload animation would be for empty reloads "Pull back the bolt and then replace the magazine".
Since MP40 has no fire selection, the alt-fire mode could be for the folding stock, which could for example adjust encumbrance (accuracy and movement speed, folded stock for less accuracy but more movement speed, open stock for accuracy and less movement speed).
MP40 has only full auto, but according to information I've read, the fire rate is very manageable to pull single-shots.
It's an open bolt firearm, meaning the reload animation would be for empty reloads "Pull back the bolt and then replace the magazine".
Since MP40 has no fire selection, the alt-fire mode could be for the folding stock, which could for example adjust encumbrance (accuracy and movement speed, folded stock for less accuracy but more movement speed, open stock for accuracy and less movement speed).