Adding a ranged weapon

I'm trying to create some background equipment for a Weird War 1 game and am having trouble adding weapons. I'm not getting any of the range properties etc. Everything I create is just an item. What am I missing?

Thanks,
Pikup

Use the Edit menu to add a new Weapon (click the brown / button at the bottom right of the items data list window) not the right-click menu.

Many thanks!