Re: .17 HMR and .22 LR once again...
22LR is great for learning, 17HMR is great for killing.
At 100 yards, you need a very good 22 and great ammo to get the accuracy of a 17HMR at 100 yards. I have a $2,000 22LR that is as accurate as my $300 Marlin 17HMR at 100. I pay $10.50 a box for 22LR ammo (Eley Match) and $12.50 a box for 17 HMR (just whatever is cheapest, because it is all made to that same spec by CCI).
When it comes to terminal ballistics, the 17 HMR is scary, especially the hollow points, though they are less accurate than the ballistic tips.
All this said, I shoot my 22LR a lot more because when it comes to rimfire competitions, 17HMR is generally disqualified or marginalized.