How do you remove a weapon from a battle set without removing it from the armoury? (I thought remove on modifying a set just took it from the set.)

Yeah, it's a bit unclear currently. The big red button that sais "remove" will remove a weapon from the armory. If you want to remove something from a set, you first click "Edit Set"button, and then you can remove a weapon from the set by either clicking the image, or the checkbox below it. The small checkbox shows you which weapons are in the set and which aren't. If you put a pin on your armory, you cannot accidentily remove weapons to your inventory anymore, since it'll ask your pin to confirm first.

Thanks