Seeing Joerg badassing the Cobra pistol crossbow was fun to to watch, but sadly enough the concept of a magazine was already implemented by pimpmycobra.com. Joerg says he has no other modifications to do and the Cobra has reached its limits to what can be done to it. I disagree - there's a modification which is unique and could go commercial: Make it shoot ball bearings. Ball bearing pistol crossbows already exist, they are "dual purpose" pistol crossbows which have a top guiding rail with magnet to guide the bearing/bolt out. (example of such a bow: http://outdoorhobbies.co.uk/raptor-1377-p.asp) but no one has modded an existing crossbow to shoot ball bearings AFAIK. Adding a "hex-nut shooter"-type magazine would be the cherry on the pie.