I have often heard that soldiers (particularly Allied soldiers) would swap their weapons for enemy weapons during World War II. Allies would take German weapons, like the MP40, that were seen as a step up from some of their weaponry. Unfortunately, I cannot recall where I have heard these rumors from.
Are the rumors of soldiers swapping their weapon for enemy weapons true? This quora post answers some questions about the logistics behind why swapping weapons is poor. As well, replies to this reddit post point towards soldiers collecting souvenirs and armies procuring large quantities of weapons to be re-chambered and distributed. My question is specifically about the exchanging of weapons for "better" enemy weapons.
I can understand soldiers on the front line taking whatever weapons are available to them if theirs suffered a catastrophic malfunction or ran out of ammunition. However, this poses difficulties when resupplying, given the drastic differences in ammunition types between armies. Even if they did manage to obtain ammunition, once they're removed from the front lines would they even be allowed to retain the weapon? I would imagine that they may even be reprimanded for losing their service weapon.