In my limited experience, I would consider 1 in 15-20 to be cause for decision. Either that's bad ammo, or bad ammo in that gun. Only once have I found rimfire ammo that was bad in everything that I tried it in.

IIRC, the only ammo that always worked well was CCI, but there may be an exception to that, too. The only rule with .22LR is that there are no rules.