If you equip an weapon in pipboy that you have more than 1 of, and then go to aid section use weapon repair kit to repair it to FULL, and then go back to weapons and select another of the same kind. Then the weapon you just repaired to full will disappear.

It is evil, if you don't notice it.

I had this happen to me. It isn't gone. If you open a container and dump the gun into it, the guns will "split up" and you'll have both again. Just add this bug to the long list of shame and embarassment both Bethesda and Obsidion should feel about screwing over their fans. FYI - they sold 5 million units of this steaming pile of crap. See what a massive advertising campaign buys you, everyone? It tells the reviewers to ignore the problems, deceive gamers and hook customers into buying something reviewed as a 9/10 when it should be a 5/10.

Bethesda and Obsidian - Go [censored] yourselves.