My experience would lean into the HMR especially if you plan on shooting a lot.  Ammo availability and cost both favor the HMR as being the most practical.  

IMHO you can find reasonably priced Ammo.  

PH

 Accuracy with the rimfires varies greatly from lot to lot from the same manufacturer. I’ve been through all of them and the one rimfire out of the bunch I ended up keeping was the Mach2. Great little cartridge, I can consistently hit Starlings out to about 80 yards. Mine is a Ruger 77. You don’t see much Mach 2 ammo on the shelves but it is readily available from the online sources. That being said, I would step it up a notch and go with the 17 hornet in a CZ platform. I was shooting the 17 Ackley Hornet long before the 17 Hornady Hornet was introduced. It’s an absolute laser beam out to about 200 yards with accuracy that puts the rimfires to shame. I know a few fella’s that bought the Savage (salvage) model 25’s and they are just complete junk. The CZ’s shoot very well for factory rifles but the price has gone up substantially since they have been discontinued. (because they shoot very well) The only thing I don’t care for with a CZ is the back assward safety’s. You can always go one step further with the 17 Remington which is basically a 222 mag casing necked down to 17 caliber. I own 2 of these little fella’s, one is a Sako and the other is a Remington 700 LVSF. The Remington gave me some trouble initially with accuracy until I got rid of the Tupperware stock and put real piece of wood on it. The Sako shoots lights out. Hope this helps more than it confuses……….

Erin