I noticed a problem with a magazine the other night. It's a factory one, worked fine until now. When I was unloading it, the after three rounds the follower stopped moving up. I turned it upside down and dumped the remaining rounds out. I used a pen to push the follower back down, and when I removed the pen, it popped back up to the top as normal. Is it a worn spring? I haven't shot more than 200 or 300 hundred rounds through the pistol. So that's only about 100 to 150 rounds through that magazine. Any ideas? Thanks