Please, note, only the standard target bolts will work with the magazine.
Nevertheless, in order to use it without the magazine, you would have to replace the trigger mechanism back to a standard one (can be purchased here:
https://ballista.co/crossbow-shop/parts/trigger-system-for-mini-crossbow-ballista-bat-reverse-edition/
And you can mount a top picatinny rail on top of that standard mechanism, if you need one (which can be added in a custom order, if you would like one).
This way you’ll be able to use it with regular bolts, such as 12.8″ practice ones, or Sting (13″-16″) hunting bolts.