After many adjustments on the rear sight, the screw came out with the spring. Umarex said, since I purchased the air gun from Amazon it may have been defective as Amazon buys products not knowing they're defective. They also said my pistol has been discontinued and they're happy to replace it with a Rugers Mark IV and it has a red dot. Viewing the responses in this forum, I wanted the opportunity to try the red dot but thought I had to wait. The defective air gun is a blessing in disguise. Meanwhile, the HOSP are accumulating, temporarily! Thank you for all of your advice and support. So grateful to you all