To duplicate a weapon you need a bow and arrows along with what you want to duplicate. walk up to a wall ,not too close, with your bow and arrow in hand, notch an arrow keep holding the right trigger ,press B to your menu ,press A on the arrows you have equipped and drop whatever you want to duplicate ,press B out of the menu along with letting go of the left trigger and duplication. beware that lockpicks may freeze your xbox or glitch a lot, but no damage to your box.