[Rifling]

One, You don't know jack shit about guns.
Two, The original M16 in Vietnam was the M16VN.
Three, Its The Avtomat Kalashnikova, Made by..obviously Mikhail Tomofevich Kalashnikov. And it didn't have three firing modes it had two. They were FA, and SA.

Notice how all the rifles you said were "Assault rifles" are fully auto?
The M16VN was FA and SA, and the M16A1 was also. The VN had small, fragile parts that were easily jammed, and A shorter barrel doesn't create a lower velocity, just a shorter range, stop reading off from the SOCOM website or whatever. In the M4A1's case penetration actually helps with a smaller barrel. DOn't ask me why, I just have read about it...M60 Classified, and the rest? What..you haven't got that far in the game you ass?

Quit pretending like you know what you're talking about ass gnome. (Talking about Megalith.)