Of course at teh time of the NFA enactment US forces in China were issued some of the Thompsons. I can not speak about Marines in Latin Amererica at that time perhaps someone else can. In any case the short barreled shotgun was chosen primarily because the case could be fraudulently argued that it had no military usage as if it had such a usage then it would have been unconstitutional to tax it the way the NFA did.
Stay well - Stay safe - Stay armed - Yorktown
I've said it before, and I'll say it again, if the Swiss can have full auto, so should I.