22 Magnum still a viable choice @ $15 per 50
Which is more than double what I pay for 17Mach2.
17 HMR smokes it in performance, availability and price $19ish per 50 available locally
That is triple what I pay for 17Mach2,and I can load my .223 which greatly outperforms the 17HMR for that price.
If you are set up for reloading you can load 22 hornet about as cheap as either of the 17s from what I've heard
Certainly cheaper the 17HMR at your price of $19,but not at the price that I pay for 17Mach2.
Can they be bored out to 17 HMR if the owner chooses?
Apparently you are unaware of the fact that the 17Mach2 and 17HMR use different length actions.
The attraction of the 17Mach2 is that it provides a fairly flat shooting cartridge out to approx 150 yards,and in most rifles,it tends to be more accurate at 100 yards and further, than most 22lr guns using low priced ammunition.In order to achieve the same level of accuracy with a 22lr,you generally have to use a higher end ammunition,which costs just as much or more than what I pay for 17Mach2 ammunition.
You can still buy a 17Mach2 for $200 or less.With you paying $19 for 17HMR,and me paying $6.50 for 17Mach2,I could save the price of the 17Mach2 rifle in less than 1000 rounds fired.If you fired 5000 rounds of 17Mach2,you would save $1250 compared to a 17HMR,so even if they quit making the 17Mach 2,you would have paid for the gun,and be $1000 ahead.
And by the way,the prices that you are posting,indicate that you are paying far more than you need to for your 22mag and 17HMR loads.