We have a guide for Battlefield 4 helicopter rocket options, courtesy a player who has field tested the rockets and has contributed the gallery you see below.
Let’s go straight to the damage output: Hydras, with 14 rockets, do 86 damage. Zunis, with 8 rockets, do 78 damage. Finally, Smart DAGRs, with 10 rockets, do 61 damage. The TV Missiles do 41 damage, Gunner 30 mm Guns do 33 damage, and the TOW Missiles do 26 damage. However, these don’t tell the whole story.
OK, so if you’re good at aiming you will want to stick to the Hydras for the most part. Zunis can do more damage per rocket, but at the cost of low capacity and poor firing speed. Smart DAGRs do drastically less damage and have a lower projectile travel speed. On the other hand, those same DAGRs are a good choice if your aim is not the best, or if you enjoy dogfights with other helicopters.
The Gunner 30 mm Guns are good to pair with any other missile except the Smart DAGRs. The guns and any well-aimed missile combination can take out a tank with a single strafe. Meanwhile, TV missiles only do 41 damage, but give you a mobility kill. What this means is, when your gunner pulls off a TV hit on a vehicle, you can bring the rockets in and take that now-immobile vehicle out. TOW missiles only do 26 damage, but it does have one thing going for it: it locks on to laser designated targets. Two locked on TOW missiles can take out a single MBT.
As you see, the best pick depends on what situation you will often find yourself in. Check out the gallery below for even more information.
Source: Reddit
