Well first of all a 17hmr is no more accurate then any other round!!!
I'm not sure if you mean at 25-50 yards. But I can assure you, even promise you that at long ranges (100-150 yards with a rimfire) the .17 HMR is much more accurate. I mean honestly, its a tack driver. I've got both a .17HMR and .22mag in a 917 Marlin. Night and day difference in the two. The .22 mag will shoot a 2-3 inch groupat 100 yards. The HMR will shoot smaller than 1 inch group. I know many people with both also and they shoot similar. Please don't take that as I think they are better than a .22 mag. They both have pros and cons.
The .17HMR pros- It is an absolute tack driver, longer range, explosive on small varmints.
cons- ammo is expensive, it doesn't carry enough energy for longer shots on bigger varmints (coyotes, fox, etc)
My .17HMR is my "crow bustin" gun. It is sighted in at 110 yards, anywhere out to 125 yards I hold the crosshairs on the center of crow- dead bird. 125-175 yards, I hold on the head of the crow- dead bird (If I do my job). 200 yards I hold about 2inches above birds head. I haven't killed to many this way (60%), not many shots either though.
For squirell's, rabbits, etc I prefer a .22, coyote and fox a .22 mag.