It's possible to carry 2 rifles a the same time by putting one of them on the back and the other one in your hands(you need to scroll and choose "Take gun in hands" and have the other gun on your back). If the player that has 2 guns log out, the gun that he was holding in his hand will be dropped on the ground. Other players can then pick it up. The player who dropped the gun will keep it in the inventory, when he log back in. The gun won't appear on the player on the back or in the hands, but in the inventory by scrolling down.
I have only done this with "bigger" guns like th M4 or Mosin, but not with any pistols.