What do want to use it for?I bought a Ruger .17 hornet this past summer.It's a great varmint and fur gun but the gun itself is more expensive.It's also not really for plinking or for small game that you plan on eating.
I'm seeing quite a bit of HMR in 17 gr but not in 20 gr. Unfortunately, my Savage likes the 20's . I don't think that it's unusual for the Savage HMR's to be finicky when it comes to ammo so while HMR ammo may be available, a load that shoots accurately in your gun may not be. I'd favor the centerfire too, especially if you can reload.You'll get more versatility out of it.