An old brass hose nozzle emerged from my garden hydraulics toolbox when a much newer plastic nozzle failed. Unfortunately, this one leaked a bit too much to serve as a replacement, so I grabbed it in the vise while pondering how to disassemble it:
It turns out the knurled ring is threaded into the nozzle and, even at this late date, responds well to gentle persuasion with a Vise-Grip:
The washer is a lost cause, but I managed to find an O-ring that fit perfectly in the space available. Clearing some crud around the nozzle hole and buffing up the matching conical section improved its sealing ability, so I’ll call it a win.
The word ITALY stamped opposite CHAMPION suggests this thing might be as old as I am; it’s been a while since either brass or Italy was competitive in the world of cheap manufactured goods.