Early on in the introduction of the .17 HMR, I was quite sceptical of the round thinking the .22 mag would do just as well, just needs to be held a little higher. After a few months of reports here and at other forums of exceptional accuracy, I had to see for myself. I had a Ruger 10/22M (.22 mag) I wasn't using much and converted it with a Butler Creek .17 HMR barrel and stock (set). I had originally thought of getting the 452 Varmint in .17 HMR also but decided to go the cheap route first to test the cartridge first hand. After a few teething problems that were solve with some investigation and replacement, I have found that the .17 HMR is truly an exceptionally accurate round. This is considering the BC barrels aren't known for their accuracy. (I based my 'exceptionally accrate' rating as compared to its .22 mag performance.)
[Problems with .17 HMR hanging up in the 10/22M mag. Solution was to loosen bolt of the the mag by ~1/8 of a turn with an Allen-type wrench. Tasco SS 20X scope broke and was replaced by SWFA.]
Some of my results can be found
here.
Currently working on why I am getting one shot fliers (1 out of 9 rounds in a group). I had found on my last outing that on occassion when the crosshairs of the scope were ~0.50-1.00" above the center of the target, I was applying a slight pressure downward on the grip just behind the reciever. Since the BC stock isn't free floating, this applied a pressure (from the front rest) to the bottom of the forearm upward on the barrel and a very slight shift in POI. I've since freefloated the stock but have yet to shoot groups. I did get a 0.40" 5 round group at 100 yds one time in the last outing but this is abnormal as I normally shoot a full mag for groups. (Had to stop at 5 as it was the best group I had ever gotten from a semi. I knew I would have screwed it up if I went the full 9. I don't consider it an official group but one to think happy thoughts about. Rest of the 9 round groups were 1" +/- 0.125". This was before I figured out my flier problem.) The converted gun has shot exponentially better than in its original .22 mag configuration.
Note : The 10/22M has a steel reciever. I don't mind freefloating a steel bull barrel on it as I think the reciever can handle it. I'm hesitant on doing it on a regular 10/22 with the aluminum alloy reciever. There are aftermarket steel 10/22 receivers out there.
In short, I am a .17 HMR convert.