breech question

Changed barrels and decided to clean the works, inside the frame, hammer, spring etc. Lubed the hammer guides with a slight film of silicon. I rezeroed the scope today and noticed that the breech knob rotates to center with each shot. Never did this before. It doesn’t affect the accuracy. Haven’t checked the muzzel velocity yet but thought that I would ask if anyone has any experience with this.

By the way in a previous post I was having an accuracy problem. Thanks to your input a simple change to heavier pellets has taken care of the problem.