Interesting little thing I noticed...

If, when carrying the PR and SMG combo, you carry the PR in your right hand and the SMG in your left (opposite of how people typically carry it), it helps a lot in close range.

Think about it this way: Ever charged into a fight with that combo and had it finished via melee? I know I have. Well if you carry the combo normally, then you melee with the SMG. But if you switch hands, you'll melee with the PR, which seems to be a much more powerful blow, and somewhat faster. Who knows? That split-second could mean the game.

Try it out, let me know if it makes a difference.