Just sitting down after admiring my work installing Meprolights on my MK 23 and USP Expert .45. I bought a Fisher Sight Pusher a year ago and the sights shortly thereafter and just finally got the time and nerve to do this myself. The MK 23 was fairly straightforward. The Expert needed more attention. Thanks to postings by Big Bore and TooSixty, I was confident enough to do the rear sight on it. Front is simple - push out old, push in new. The rear sight requires removal of a roll pin, the firing pin block and spring and then sight removal, sight installation and reinstallation of block and spring and pin again. The geometry/shape of the slide and the same issue on the adjustable nights sights required some workarounds to make everything line up and not mar the slide or ruin the sights. A smith could have done it faster, but then I would not have the satisfaction of tackling this successfully on my own. All is well now. Both pistols are still virgins till range day next weekend.