In regards to the slide not staying back after the last round. I had the same problem with one of my magazines. When I examined it I found that the follower still had some flashing from the moulding process. This prevented the follower from moving as far up toward the top of the magazine (compared to my other magazines). I removed the follower from the magazine and rubbed it on a piece of sandpaper following the tapered contour of the follower. I went slow and reassembled the magazine several times untill the follower extended as far up in the magazine body as the others. When it matched the others I put it in the gun, pulled the slide back, and insured it would lock the slide when empty. It is now my main magazine and works fine.