A modern improved version of an ancient chinese weapon, the Chu Ko Nu. They had an overhand hinged pump action that grabbed the string while forward and cocked when it was pulled back. It also had a kind of fixed box magazine for the bolts. Like the modern version it was not very powerful and had a lesser range capability. However, the chinese used to poison their bolts. It made for a very lethal weapon and some examples found in chinese tombs have been dated at a few centuries BC. They were even used almost right up to the 20th century, against the japanese at that time. I had seen one of them back in 1979, pretty amazing engineering even by near modern standards, actually.
