I'm not disagreeing with Cast, but I really do mix up the 22LR Ammo in our 22's, and it all shoots fine. But "fine" is a subjective measurement in this case. For the absolute best in accuracy, I'd have to test ammo. I can head shoot a squirrel at 30 yards or so with any ammo I have, and that's good enough for me. Of course, I'm blaming the misses on me and not the ammo.