Only tradable goods will fill your cargobay.
No weapons or mission cargo will do that, at least not in an unmodded game.

I know that Rebalance and TNG have engine-upgrades and hull upgrades and such. Those will fill your cargobay.

The Titan Flies Like A Cow

Yeah, just sell your extra guns and turrets. There is absolutely no need to carry 3 cruise disruptors...

---Everything is evolution---

Weapons are small and don't take up much space. But no sense carrying any you don't need. Save the more powerful weapons for when you can buy a ship to use them and sell of the rest. (e.g. When you recover Level 10 weapons from a wreck and are flying a ship that won't fit more than Level 6, hang on to the guns!)

Now missiles and mines do have a maximum storage space, unlike guns and launchers. You might find there are drone mines or wasp missiles that you cannot tractor in, since you run out of space for them.





Juni: "Trent, we've got to go faster!"