I have a stock TM M4 barrel, and it's as tight as a...well something tight. Anyways, take off the upper foregrip piece (or upper RIS rails if you have them), and tighten all the hex screws you see. There should be 3. Tighten them up and put a little LokTite on the threads. Put the grip back on and tighten the slip rig nut (piece inside the Slip/Delta ring). That should do it. Beyond that, there is nothing you can do. If you want to bring it to the BT game this weekend, I will help you. The TM barrels are 3 piece, so where they meet must be tight. When it gets wobbly, tighten them up. It's easier for you if you don't have the RIS, the round grips lift right off with a pull of the slip ring.
The CA barrels are one-pece and more snug as a result. I don't think you want to spend the dough on one, so just do as I said, and you should be OK. Remember that rough handling and the use of a sling will worsen this, but it can always be tightened up again, no permanent damage. I just got a metal body, and decided to keep my stock barrel because I got it so solid. Chamber blocks, barrel strenghteners, one piece barrels are a waste as far as I'm concerned. Of course, if you got 90 bux laying around...