To fill a paintball bottle from a fire extinguisher cheaply could I take the nut from the extinguisher, turn it on a lathe to open up both sides so I can screw the paintball bottle in one side and the extinguisher on the other? Would the nut be able to cope woththe pressure? And because the nut will only be half screwed onto each bottle will it be held on enough?

I know that I should have a dump valve in-between the two bottles but i think I should be ok?