Firing pin issues?

[LS-208]

I have a walther p22 that has only had maybe 500 rounds fired thus far. The firing pin is hitting the rims but only 6 out of 10 will discharge. I am wondering how to remedy this problem myself without sending it back. Sometimes i fire the Colibri super-sonic ammo and have a major issue with the extractor not extracting the cartridge. I am going to assume this is a problem lying within the thin rimmed cartridge. If anybody has any insight on how to remedy this problem, I would be very appreciative. Thanks!

[BearTaylor]

I once had a brick of ammo that was a pain to put through any of my .22 semi-auto handguns. I went to CCI Stingers and no more problems. I ended getting rid of the ammo in my old .22 Winchester pump rifle. It fires just about anything.

[Booga]

I also have a Walther P22. In the manual, it says 500 rounds is just the break-in period.
I've put maybe 600 rounds through mine, and maybe had six misfires along the way. I'd say four of those fired on a second strike(love the double-action for that). Extraction has been near flawless. The only time I saw an extraction failure was when I gently let the slide down, so it was user error.

Unless you've got a bad batch of ammo, I can only think of sending it back to the manufacturer or buying another type of ammo to see if you can duplicate the problem.