It seems that there is more problems then just ammo. Weapons placed on WF maps are incompatible with attachments. If you attach something you get sound, but attachment is removed. eg. a match sight I found in Omerta fit correctly on Glock 17 my IMP had, but it got deleted from the game when I tried to place it on M1911 I found in sector. Or 2x scope when I tried to place it on Ithaca 37 or on Type 85.