Originally Posted by PistolRogue
Try running the follower up and down in that spot with the mag out of the gun and no balls loaded and see if you can feel it hanging up on anything. While the build quality of the mags seems pretty good there's nothing saying there couldn't be some casting flash or something on the inside that might be catching the follower and causing it to drag.
Good idea especially paint or dirt will make it hang up. It could be your spring is too soft also but I bet there's something getting in the way. You can always stretch the spring a little to get some tension back too(not the correct way to fix it but it will work as a quick fix)lmk what you discover.