The American version had some small flaw, however, that made it a poor weapon when mounted in the wings, with jamming issues and such. That's why the P-38 successfully had the M2 mounted in the nose!
Not really. P-38s had the same problem that was basically solved with lots of grease. For some reason we refused to adopt the British solution of changing the chamber length by about 1-2mm (I don't recall if it was longer or shorter off hand). Wing mounted guns of all kinds are more prone to jamming.