After spending a bit of time shooting a friend's .17 HMR rifle, I decided what I really wanted was a Ruger .17/45 Lite -- but those don't actually exist, and I couldn't find a smith willing to take on a conversion.
After putting a couple boxes of .17 HMR through the Single Six (which shot well, and had almost no muzzle jump) I don't understand the attraction of that round in a short barrel: 50% more expensive ammo, flames shooting out of the muzzle, and far more blast pressure on my face than I get from my 20" 6.5 CM.