I had these TFX sights installed by a gunsmith, pointed out the gap and he said that is how it is supposed to be. If you can't see in picture, there is a gap between the sight and slide, as well as under the dovetail section. Had the same sights on my Shield before I sold it and it did not have the gap. For what I paid to have them swapped I could have bought a good sight pusher. Thoughts? Thank you.