a turn is 2 actions
Okay, that makes sense now.
I think rocket weapons are balanced. They are more powerful, but they use ammo, which is limited.
And even though you can boost ammo with modules, it means those module slots aren't being used for health.
Although, if you're a level 9 facing a level 12, most weapon can kill you in a few turns.
So overall, all the weapons are balanced for their own levels, but I agree that the difference between levels may be a bit high.