I find the KCI Mags a bit hit/miss but learned to correct them if they don't function properly. They have a couple of issues. One is when the plastic outside shell is baked onto the inner steel insert, there is all along the walls protruding plastic points that need to be sanded or filed off to make the inside wall as smooth as possible. This is where the spring gets caught and then the follower simply does not want to come up despite the spring load and rounds still present in the magazine. The second problem may sometimes be the spring that is sort of twisted around and no longer copies the rectangular shape of the magazine and again on an occasion gets stuck. Straighten the spring so it's all straight and uniform, lube slightly all the sides of the follower and you'll have properly functioning magazine for much less then the OEM.