I have one gun but I am not sure if I have the 24v PSU. Do you have a picture of what they look like by any chance? I do have a 24v PSU that came with my Time Crisis kit (where this gun may have actually came from now that I think about it) but I don't know if that would work for your setup. I have never used the 24v PSU though.
I have not tested the recoil in the gun however as I don't have the right setup for it, but I do know the gun actually works without it since I've used it that way.
Shoot me a PM if you are interested.