The projectiles for the .17 HMR are .172 I think, but I haven't pulled any down to see. Seeing as how it is a rimfire round, I don't think that they are available for purchase to reloaders, as you can't reload them.
Thanks I tryed some new (to me) airgun ammo its RAPTOR from GAMO. It increases the fps 25%. It has no lead and is GOLD plated. It makes my 1000 fps airgun shoot at 1250 fps, that is shooting a supersonic!Airgun. Anyone tryed this stuff?