Not that I'll admit to doing it because it'll elicit howls of protests here, but you can easily do it with a couple of pieces of virgin brass. Do NOT load them or seat a bullet, you only need the brass itself. Take a piece of scotch tape and put it on the head of one piece & trim it around the edges with a knife, this becomes your NO-GO gauge (scotch tape is about .003" thick). Use the other piece for the GO gauge. Screw the barrel into the receiver with the bolt closed until it stops then back it out a couple of turns, put the piece without the tape in the chamber (the GO gauge) then gently screw the barrel down until it stops. Take that piece of brass out and insert the one with the tape on the face (the NO-GO gauge) and gently try and close the bolt. It shouldn't close. Tighten the barrel nut down and recheck them again to see if anything has moved. There really isn't a need to remove the ejector, it'll retract just fine.
Theoretically I might have done this multiple times and every one of them has worked perfectly. The first time I rebarreled a savage I bought the headspace gauges, after that I decided it was a waste of money. Attempt at your own risk.
