Originally, submachineguns (as the name implies) were designed to be CHEAP and easily built machineguns, that could be carried and fired by one man.
to my knowledge its the latest one they've brought out and it chambers a simliar round to the P-90 so its designed to penitrate armour like kevlar
the drum magazines were heavy and they also rattled. the box magazine in my opinion was much more efficent and more comfortable to carry
i dnt kno but to my knowlege they were never taken into military serivce because of the reasons ive stated previously and that is also why the M1 and M1A1 thompsons couldnt take drums magazine becvause they werent being used. but yeh they do look kl but only on a M1928 with a pistol fore grip
I think that's correct. For WW2 anyway, the US military used stick magazines. The stick mag was much better suited for military use as it could be easily reloaded from stripper clips, took up less space, easier/faster to make, etc. The drum does look super cool though. The Tommy Gun in the pic above is what most folks think of when you mention sub-machine gun.