compressed air pistol nozzle

i did this quick and dirty design to be prepared if i ever need a "special" nozzle for my mini compressed air pistol. this one is not special yet, but at least i could test the thread and the hex part with my air pistol (and it works ;-). don't ask me, what kind of thread it is... i just measured it roughly and modelled it accordingly... i also don't have any idea, if this is used on other air pistols. mine has a marking "g4" on it...