Depends on which of my many 22 rimfires I happen to be using. For casual plinking with the mossbergs, Dynapoint is hard to beat, but PMC Moderator is very accurate at modest ranges. The 541's like two or three types of target ammo + an old lot of PMC Zapper unplated HV stuff that I am hoarding. Lest anyone think that this stuff doesn't shoot, I have twice won 100 meter benchrest matches with it.
The 581's both like T22 and dynapoint, and several other brands give great "plinking" accuracy. 22 Rimfires are still the best "bang" for your buck out there, and give one an inexpensive way to hone the shooting skills. Regards, Eagleye.