The Sensfelder article about the Sagittarius crossbow
In late 2003, Jens Sensfelder, a German expert for medieval arms, wrote a short analysis about the crossbow depicted on the Sagittarius page f73v of the VM. It never really got published, AFAIK, but the analysis is of interest, because it gives us some hints about a possible dating of the VM.
The link below guides you to Nick Pelling’s site, where you will find the analysis in full length.
This is the image in question:
You can check it out in context on Jason Davies’ Voyager site.