About the most modern Japanese SMG going is the [url=http://en.wikipedia.org/wiki/Minebea_PM-9]PM-9[/url], although an [url=http://en.wikipedia.org/wiki/Heckler_%26_Koch_MP7]MP7[/url] might look more sufficiently badass and modern. And Specialist is roughly equivalent to Lance Corporal, though they tend to be, well, specialists rather than fire team leaders.