@nugger @Curvin
Also, do not forget the hook in front of the crossbow.
While it is not mandatory, it allows you to use your foot while reloading the crossbow, making it easier, or allowing you to put more power into it.
But I guess, it can be added to the 2nd model. The first one needs to just work 
m.youtube.com/watch?v=VlY2J4Zo6zk