From reading on other forums - Ruger had reliability issues, and from what I had seen, cycling issues and possible head case separations problems dealing with semi-auto setup.
Bolt action hardware seems to work ok, but even those have disappeared off the market.
Here is the interesting tidbit from one of the folks that designed a Ruger 10/22 style semi-auto rifle based on those rounds.
It has come to our attention that certain lots of 17HMR and 17Mach2 ammunition may exhibit performance problems. These problems could result in damage to your rifle and may be capable of causing injuries to shooters or bystanders.
As a result, we strongly advise immediate discontinued use of rifles chambered in both 17HMR and 17Mach2 calibers due to these ammunition performance problems. Although performance of ammunition is outside the control of Magnum Research, we take safety concerns seriously.http://www.magnumresearch.com/whats_new.asp