.17 mach 2

That's good to hear. Recently bought a place I can plink all I want was moving the gun locker and forgot I even had a mach 2. I'll have to start looking. If I remember right the cci black tips have an issue with the cases cracking and getting stuck.
 
Quite a bit of hm2 available.
It's all made by CCI, even the Hornady.
Ammoseek.com has the current pricing and inventory locations.
You can also purchase direct from CCI.
 
I have been able to obtain Hornady, CCI and Eley branded ammo. The Eley is older production but still shoots as good or better than the others. I hunt with the Eley and practice with the others.