The scout helicopter is by far one of the most deadliest vehicles bf4 has to offer. With that their are only two types of primary weapons... MiniGuns and 25MM Cannons
The mini guns are extremely deadly against other aircraft. If you know there is a lot of air threats or if there is a good opposing scout helicopter pilot on the other team then you will more than likely want to use MiniGuns because a one v one with you using 25MM might end up badly.
The trick with 25MM Cannons against a mini gun user is that you want to close the distance because mini guns are way more accurate at range than your 25MM. I do this by firing one heat seeker and letting him flare then fire my second one which will hit and then while he is "mobility hit" and has low power I close the gap and you only have a good 5 seconds to deal some good damage!
Granted a good opposing player will know what your up too or try to do the some thing, that's why I like to play peak a boo with building and hills to bait them firing a hear seeker and not using my flares.
MiniGuns are also extremely deadly against jets, rhib boats, helicopters, artillery, atv, dirt bike, and other small vehicles. It's also not bad against attack boats.
It can't do damage to tanks or LAV's.
Mini guns are effective against infintry but you have to be way more accurate to hit them.. Which isn't the issue, the issues is while your trying to get your aiming precise your vulnerable for longer amounts of time which might cause a stinger lock on or just a rocket to hit you in the damn face..
However 25MM Cannons have splash damage which makes picking infantry extremely easy and allows you to be more versatile with your flying. You can also damage heavily armored targets such as tanks and LAVs. One thing to note as well is that mini guns have a over heat function so you have unlimited rounds in reserve and only have to deal with overheating. However with 25 MM Cannons you have a volley of 30 and reserve rounds up to 90. You will constantly replenish your rounds but your might have to wait for them. It's the same kind of system if you have driven or flown a attack helicopter or tank.
I hope you have found this helpful!!!
- HG