I believe the P22 was designed for high velocity
Mine has failed to eject an empty case once, the edge of the case was a little torn. A jeweler's screwdriver (not down the barrel) popped it out, and it's been fine since; that was ~150 rounds ago
It was recommended to me to use dry lube on a P22 as they can get quite dirty and oil attracts even more debris.
I have used mini-mags from CCI and Winchester Wildcat ammo with no problems at all in my P22. Fun little pistol