Reloading out of ammo bug (experimental 1832)

I had a 12 gauge pistol and two types of ammo, 50 00 shot and 65 12 gauge slug. when reloading the gun, it asks for me to select which ammo to use and then tells me im out of ammo after ive picked one instead of reloading when I clearly have plenty of shotgun shells. if I drop all of one type of ammo then hit reload, it does it normally. the same goes for bows and all the other ranged weapons ive tested.