Do I need to be leading the targets to account for any flight time?

Consider the Reticule as a sight and that indicates mostly where it will go.

Now, when all Four of the cross bars are Red you have a target that can be shot in your, sort of, cross hairs. Certain targets require modification of where the Red is active. Turrets and such require aiming at the Turret for the most part and Not the structure. The structure will allow many to be destroyed but for maximum destruction aiming at the actual weapon is best.

For Mercs their feet are a good place to aim as the splash damage will still give them some hurt even if you miss them directly. It takes some practice and plain old getting used to it.

For LAVs they always crash out sooner or later. Hit them when they are recovering from the spin or bumping off a wall. They are stationary then and if you are using a stored charge variant then it is a quick adjustment to the Reticule position and releasing R1. Pop, no more LAV.

Drop Ships have similar tendencies. They need to pick up or drop off Mercs. Hit them as they ascend or descend. They will come at you and head away from you. Adjust, release and pop.

HAVs mostly move slowly but are normally bested with Assault Forge Guns, for myself anyway. The Assault charges faster, doesn't store a charge and can put several thousand damage at anything in under ten seconds. HAVs stop, turn, get stuck on buildings and will run from AV attackers. That means you will soon learn where they are running To. Be prepared, adjust reticule, press R1 and it releases on its own.

Beware that HAVs and Drop Ships will hunt your butt down, as they should. Forge Gunners are a direct threat and getting rid of them and the Supply Depots that enable them to be Fitted on the fly is a high priority for any HAV Driver with any experience at all.

Practice, practice, practice.

Thank you all for the help.

I am going to keep practicing though i did manage to kill myself twice in one match yesterday with the assault variant, it does not mix well with point blank walls and LAVs.