I ran about 300 rounds through mine today, with nary a problem... other than a couple of ftf's when I didn't push the clip in solidly. I don't expect them to feed properly if I don't get the clip in where it's supposed to be.
I had Walther look at my gun, and they completely rebuilt it because of a manufacturing defect that "chattered" the slide and gouged out parts of the slide that should have stayed smoothe. It had a nick in the trigger assembly that was gouging out pieces of metal every time it cycled, and now that this has been fixed, it's running great again. They gave me a new slide and trigger assembly.
Strangely enough, mine takes about any kind of ammo I feed through it, but it likes stingers and remington jhp's a bit more than most others. I would like to be able to get a bit better slide for the pistol, but it works fine with the zinc slide that comes with it. I doubt if anything other than an aluminum alloy slide would cycle on the gun considering it's only a .22LR cartridge, but it eats ammo like a pig, and until it gets so dirty it won't run, it just keeps on shooting... and it's only gotten that dirty after 1000 rounds or so.
I actually have more concerns with the field stripping of the gun than how it runs. It's a royal pain in the ass to reassemble, and seems to develop a mind of it's own sometimes when that's being done. I field strip all kinds of guns, and if you really want me irritated, let me clean this P-22 and my Makarov on the same day. They have just the right amount of quirks to make me crazy trying to get things back together.
As for the zinc issue, I'd like for the next designer to use something that will not destroy itself when something's off just a bit (like my trigger assembly was). I suspect that a carbon fiber slide would work just as well as the zinc one if it had a metal insert at the point of impact where the slide is driven backwards... so any of you guys out there who like to do "aftermarket parts"... here's an opportunity.
I love the gun... it's cheap to shoot, and for the most part, goes bang every time I pull the trigger. Since there's little or no recoil, it stays on target, so across the room, you could count on me putting 10 in your chest if you're not quicker than me on the trigger.
I know that everybody discounts the .22LR as a self defense round, but I've hunted all my life with .22 LR hollow points, and killed a lot of game with them. We even killed hogs with them, when my uncle had his farm... so they'll get the job done... and a chest full of them would at least have to hurt...
The P-22's not my favorite gun, but it's one of them. Great little shooter.
WT