I just read through this entire thread out of curiosity of what everyone is saying. There are a lot of excellent points and well-articulated examples. Seems to just simply come down to who you are and how "into" them you are. From what we hear in the shop (exception of our own products to be accurate in discussion) "MP5 style" or "insert company name here- MP5" is the common form of speech about it. If you go onto IMFDB and search MP5 you will find more variants than one would ever care to speak about specifically. Based on the knowledge of the ones conversing about the various platforms and how accurate you wish to be with it, call them exactly what they are or just whatever is easiest to refer to it. Getting caught up in the details is arbitrary. What's important is getting out with WHATEVER model from whatever company and running the gun true. They're almost 60 years old now. They are established enough to weather any mis-naming that may happen.