The .22 WRF and .22 WMR both shoot a .224" bullet as opposed to a .22" bullet for the .22LR. the .22 rim fire mag. shoots a jacketed bullet. Here, folks don't seem to care much about the sizes as it really doesn't matter as far as pressure is concerned, but jacketed bullets in rimfire barrels usually means rapid loss in accuracy for the softer RF barrel - or so the 'word' goes. Many .22LR Cadets were chambered here for .22 Hornets.

The reason I mention this, is I did not think it would be possible to get such a re-chamber to the RF mag. to be re-proofed in either England or Germany due to the diameter differences - bullet to groove diameter.

Dropping or raising the pin strike as well as well as extractor work would have to be done to make the changes, along with chambering and throating. The reamer's pilot would also have to be reduced in diameter - maybe.