My personal favorite idea on this would be to link a weapon to a plex storage that you would load the ammo into.
However it should not be mandatory. There should be advantages and disadvantages for both options. If you don't use ammo you use up power. If you use ammo you only use maybe half of what it would have normally.
As for the ammo we could have a lot of fun with this.
Ammo types could in some extent replace or enhance effects.
There could be nukes. Slow moving, but high damage missile.
Torpedoes fast moving long range missile, but poor maneuverability.
And the list can go on and on for missiles.
For cannon you could have armor piercing, high explosive, shredder and many many more.
However it should not be mandatory. There should be advantages and disadvantages for both options. If you don't use ammo you use up power. If you use ammo you only use maybe half of what it would have normally.
As for the ammo we could have a lot of fun with this.
Ammo types could in some extent replace or enhance effects.
There could be nukes. Slow moving, but high damage missile.
Torpedoes fast moving long range missile, but poor maneuverability.
And the list can go on and on for missiles.
For cannon you could have armor piercing, high explosive, shredder and many many more.