In A13 the developers changed the way you take apart and Dismantling things. You now assemble Weapons and other things by selecting the Assemble on any item that has the ability. The main reason for this change is because the crafting grid was removed in A13. To Dismantling something you had to put it in your output slot of the crafting grid, but with no crafting grid that no longer worked. So they came up with using this method for Weapons, Ammo, and other Resources.