There's some great stuff here, thanks...
I've just levelled up to 50 and oppened up the beast. Fired one of these at camp back in the day, great fun, and glad I don't have to carry it around for real. looking forward to a sess, look me up. Tag - drewkirks.
I would add, that the helicopters are pretty easy to take down now, nail them early. Bear in mind to use the slight zoom on your weps. (Look for lulls in foot attackers and step out of cover and only at range).
I found using the rocket launcher hopeless, and it often leaves you too exposed, same can be said for the mini gun, great to play with but you can get to carried away with it and it screws up your hit percentage like nothing else.
I would suggest booby trapping any parked SUV's or blow them clear so you retain line of sight.
The cheapest trick is to pour gas trails with jerry cans. It can get pretty impressive at night with all four guys laying it down.
The most important tactic is to cover your arcs with the other guys. If you see a weakness, fill the void.
Headsets are shite, but you can learn a great deal from the other guys, just keep it friendly.