They are not rimmed, but the 222 family of cases are just .003" smaller in diameter than the 357 Max. 357 max = .379" 223 = .376" A 222 Magnum is 1.850" in length. The problem is there would be nothing to head space on to fire form. If you could stretch the case out to start with you might be able to head space off the case mouth and use a 223 ejector/extractor. If you trimmed a 222 family case back to the base of the neck , then stretch it out, it would be shorter than the 357 Max. Bertram makes a rimmed 222, but the overall case length would be 1.700" vs 1.605", not much difference. You might get a hold of Starline and have them custom make you some cases say 2" in length. You would more than likely have to buy a large amount 10K or better, if they would do it at all + a set up fee that would not be cheap. Maybe you could recoup some of your investment by selling off excess inventory.
You might be better off to neck down a case, say a 38-55 or a 357 Winchester. Or you could chamber it for a 357 Herrett or a 357 JDJ, all of them have rims. Good Luck and Good Shooting
