Not sure if anyone here is also a member if Rimfirecentral.com, but over there, the folk have found a way to convert the 10/22 Magnum to a .17 HMR by using a Green Mountain 77/17 barrel and a washer/shim setup.
It uses the same magazine, bolt, everything else as the 10/22 mag...just the different barrel and the shim and washer to make it all work.
If anyone is interested in making that conversion for themself. Send me an IM and I can get you the instructions for the conversion. I even have some of the washers and shims available (had a machinist friend of mine make them for me).
The 10/22 is a very cool rifle in .17 HMR. Accuracy is astounding, 200 Yd. 10-shot groups
under 1.5"
Adequate power to do close-range rinfire tasks, flat shooting within rimfire ranges and decreased ricochet hazard.