What about a MP-44? There is also the fact that no one currently makes ammo nor has any been produced for over 60 years. Seems there is a condition concerning ammo supply for c&rs.
A MP-44 would really be a relic. I think that I only held 2 legal MP-44s, but handled more than a dozen MG-42s in the 2 years at a Class 3 Dealers store.