Two of my 17 Hummers shoot the 17 gr. V-Max (Hornady) and the 17 gr. Speer TNT's (CCI) so close to the same POI that I don't have to change my scopes or my aim. Did try Remington and Federal ammo too, but there was no need to look further for these two Hummers. In the third Hummer I've only shot the 17 TNT's, which it also shoots very well, so again I just settled with what works. I no longer post what the groups I've shot were - don't want to listen to the ridicule.
As suggested each Hummer will dictate which load and lot it likes. But if bug hole groups are your goal, once you find what it likes you also need to buy your ammo in large quantities of the same lot. Same with the 17HM2 rimfire ammo, although the two of the three of mine that I've shot so far really like the same ammo from the same lot. I bought a ton of the preferred loads/lots of both HMR and HM2 ammo, so I am good to go for many years with all of my 17 cal rimfires.