I'm aware that this is an old thread, but I had the need to take off and replace the rear sight of my M&P 9Pro so I could replace the striker block with an Apex Ultimate Striker Block and spring. The Wheeler pistol sight pusher was/is on sale for $113 at Brownell's. I have 2 other sight pushers (sub-$75) that wouldn't budge it. Bought the Wheeler, followed the set-up directions, which are complicated but clear, and got the sight off and back on without issues.
However. let me tell you, that sucker was on TIGHT. After removing the set screw, I set it up in the Wheeler and began the removal per the instructions. They said, don't apply excessive force, but I was sure something was going to break....then "CRACK"--a loud popping sound, and it began to move. Nothing broke, all was well and it was easier (but not easy) putting it back after changing the striker block.
Wow-- a great tool, built like a tank, but the M&P rear sights (at least mine) gave it and me a run for our money.