It is possible to modify the UCL for use in S&W magazines. You can find the info on the Net somewhere. But a couple of shops are doing the mods and reselling models for the S&W and Beretta. Amazon has them listed and Speedbeez the 617 speedloader company is doing them among others.
When it comes to loading 22 pistols mags there is the UCL and everything else is a distant 2nd place. Take it from a competition rimfire shooter.