During two recent restorations of .22 rimfire rifles I encountered excessive headspace caused by wear at the bolt root/receiver interface. This caused inconsistent ignition and swollen cases. I got the idea to solder a shim to the bolt root to correct the gap. Luckily I had some old carbon steel feeler gauges left over from the days when cars and lawn mowers had ignition points to adjust. I tried the gauges until I found one of the proper thickness. Then I roughened it (and the bolt root) with 100 grit paper and cut out a section with the Dremel tool. Next I flattened out some tin silver solder wire into a thin sheet. A piece was cut to match the shim. The bolt root and shim were coated with acid flux and assembled with the solder sheet in between. I heated it with a soft propane flame until the solder just melted. After cleaning things up the headspace problem was cured and it fired 100%

Great solution!
Necessity is, indeed the mother of invention.

Yeah, I think my only bad association with excess headspace was a worn Winchester '04 single shot that used throw up fragments of metal that hit me in the forehead on occasions. Fortunately it got lent to someone who didn't give it back (but was not blinded, just let it rust).

Maybe your idea would have fixed it. The barrel and action were one piece, so nothing else would have helped