During the Korean war I was issued the M-2 it would frequently jam with the 40 round clip. But with short burst very accurate.
I have several M-2 magazines for my carbine. One has to steer clear of any aftermarket 30 round clips and only use M-2 clips.
Those 40 round clips must not have been used as much. I hadn't heard of 40 round carbine clips before. The supply of them must have dried up many years ago.