I dont have alot of experience with a 22 mag but I have spent alittle time shooting both thru a chronograph. Lots with the 17HMR.

In my rifles the quoted fps for the 17 HMR was actually considerably lower than what I got. My 17 gr. Vmaxs were going 2650 and more. I love the accuracy of the 17 providing there is no wind...like a dart.

I never had that kind of accuracy with either of my 22 mags and normally the bullet speeds were not up to specs falling 100-120 fps short of what it says on the box for 40 gr. bullets.

With all that I would still rather have the 22 mag if I thought I would be shooting anything over 12 lbs or so.