Welcome aboard doctorknow. I hate it you've got such a tough start here, but you have to admit you've jumped head first into a fairly controversial subject. I tend to agree with the others on here, but I do have a question and some comments on your choice of firearm, not the caliber.
Did you mean to say you shoot mini-mags out of it? I haven't seen a .22 magnum P22.
As to the Walther, I'm glad you've got one that shoots reliable enough to trust it with your life. I'm apparently somewhere between you and Timothy. I like my P22 and enjoy shooting it. However, I have to run cci mini-mags to get any kind of reliability out of it, and, even then, it's not the 100% I require to carry it for self defense. I have carried it before, but I also started shooting it more during that time. That's when I really realized how unreliable it is for me even with quality ammo. May I suggest, if you insist on carrying a .22, looking into a revolver? They are much more reliable in the .22 platform than autos and capacity is similar these days.
Again, welcome and glad to see you're out there promoting your right to self-defense.