I had just started and been playing for a couple of hours when I got an automatgevär 4 then came across a better one later. When I picked up the other to compare the two I clicked X to move one next to the other and accidentally dropped it on the other gun (like ammo stacking). When I did this one of the guns disappeared from my inventory, but if I try to equip 7.62 ammo to the one that is still visible in my inventory the other “ghost gun” shows up on the selection menu. Is there anyway to get rid of the invisible gun or some solution? I really don’t want to start a new character, but I also don’t want to have to deal with an extra gun that I might accidentally attach something to… I play on Xbox.
Seems the developers are aware of the issue, hopefully your issue will be fixed in the near future.
Ok so this thread popped up and I saw that you wrote this in April. Can imagine that the AG 4 you mention has been swapped out some time ago 
Did you ever solve this issue? Has it happened to you again?
I’ve had some issues with weapons like you’re describing, most times it sorts itself out by dropping the weapon in question. There’s been multiple scopes attached to it all of a sudden or things like that.
Yesterday I picked up a grenade that vanished in my inventory, probably lying “under” something else. Much like your issue with the AG 4.