Once you unlock 25mm, it's infantry killing capability is night and day. Minigun's only real purpose is Air to Air fighting. Or if the other team is just so ultimate morons that no one decides to AA on you, you can just close in on them (like point blank range) and spray one time to kill them constantly (but someone always goes AA).
You can also GTA pretty easily with 25mm, as its easy to kill repairing engineers (game's pubbies are getting worse every single sequel, so not many spawn as engineer on gunner to fix you up) and just take the tank/IFV for your own. Just make sure the helo doesn't go into enemy hands by destroying it.
Another lulzy thing you can do is to use laser guided missile on fixed turrets (or mortars with idiots operating next to it). They are happily firing away at something, and BOOM! You get extra points for destroying turrets too. Hainan rush first base has at at least three fixed turrets (TOW included), which someone mans, as its best way to halt beach assault, so you get plenty of unsuspecting/suspecting-but-no-choice victims.
EDIT: If you want to unlock things fast for Scout Helo, just repair repair repair on it, as a passenger. You still get points for Scout Helo, even if you are a passenger. Heck, you can even help it out by either using Stinger for AA, or RPG or something for Anti-Ground.