First off, The rim fires are never a recommended caliber for personal defence. At least not as a primary firearm caliber.
Reason being the rim fire primer is not as reliable as a center fire. NOT because of power. But I will add, that IMHO the 22M lacks bullet diameter to get any serious consideration. At least against 2Legged problems.
Now having said that, coupling a rim-fire into a semi auto for personal defence, is making a bigger problem worse, as that misfire, should it happen, causes you to have to manually rack the slide to chamber another round. But if you where to have it chambered in a revolver, specifically a double action revolver, if the cartridge did misfire, simply squeeze the trigger again. Personally for life and limb I would choose a center fire as a primary carry gun. But as a back up or as a hiking, trail or camp caliber its a good choice. (No life on the line)
I have a couple 22M I carry as back ups and a S&W that's a camp/trail/ATV gun. The "trail gun" is a cherished S&W 651 in 22Mag. It shoots my limited supply of the Federal 50G HPs very well. Its big enough for larger critters live Coyotes or big feral dogs. Easily puts small game in the pot and isn't a big recoil but does have quite a loud crack to it. Before I got the S&W I had a 6" AMT 22M auto. This shot very well until I blew out a case and destroyed the barrel. I bought a 4" barrel to replace it, but it didn't shoot very well so I sold it to buy the 651.
I have also seen the Critical Defence offering in 22mag. From what I hear, its not going to be on the shelves till the end of June.
CW