I've been pretty impressed with Winchester Dynapoint. You pay more for it but it seems to run nicely in anything. I don't have a P22 but I have heard of good success with Dynapoint in that particular gun.
Got a P22 a month or so ago. Tested it with minimags, rem blue box, aquila std velocity and interceptor, stingers, some hv PMC, etc etc. Lots of different stuff I had laying around because I'd heard the P22 was finicky.
Pleasantly surprised to find it would feed and eject everything thrown at it.
Accuracy sucked though. Shot high and left with 2" groups at 10 yards. Tried every thing I could think of and that's the best it would do. With my Buckmark I can keep a ballistic polymer 3" spinner spinning at 20 yards. Couldn't even hit the darn thing with the P22.