I’ve seen a few universal sight pushers but have never used one. Do any of them work with the M&P?
I just used this one last night:
http://www.brownells.com/.aspx/sid=55697/pid=27634/sku/Uni_2ool_Universal_Sight_Mover
The rear sight is a hair wide, but I was able to install them just fine without marking the sights.
Not universal, but it works for front & rear sights on the M&P series…