I pretty much only use the UMP .45, I have killed guys up close and on the complete other side of the map with it.
The only class I use assault rifle for anymore is for killing nuke boosters. For that I have the ACR w/ Launcher and RPG x2 for the secondary. Semtex grenade with Lightweight, Marathon, Sit-rep (you can see the tactical insertions better).
I spent almost my whole time playing on saturday finding lobbies with Boosters. I can’t stand when everyone else is trying to play a legit game and these little fags are in some corner shooting themselves.