I'm not sure what the 'Best' rimfire handgun is, but, since I don't shoot any rimfire pistol competition and just plink, and/or, small game hunt, I bought a Browning Buckmark 5.5 Field model years ago. I have never had any kind of problem with it after thousands of rounds through it. This little sucker shoots well enough to enter into any type of rimfire pistol competition. Great trigger and accurate. I recently got a Ruger Mark IV 22/45 Lite. It's not a bad little pistol, but, my Buckmark will out-shoot it all day long.