Hi everyone, sorry in advance, I'm probably going to bum everybody. the failure to extract has nothing to do with the recoil spring or guide rod. I have had this issue randomly since I got the gun about a month ago. I thought it just needed a break-in period. Now, after about 1200 rds, I still have the problem and more.
What I found is that the magazine is interfering with the slide. The magazine well is oversized I think. It allow too much clearance. On mine, the mag can move about 2.5/3mm laterally. It's huge! On the polymer Q5, it's only 1mm max. My slide already has witness marks. I talked to Walther today, I'm shipping mine to them tomorrow. I don't really how they can fix it, unless it's those plastic guides that are not thick enough. I made a video of the issue, I will post the link as soon ad it's uploaded tonight.