pro m&p 40 .40cal 40s&w

Hello everyone.... i have a 5 inch Pro CORE 40 that I'm having some difficulty chooseing the correct red dot for. i tried two and can't seem to get it too zero or co-witness for that matter. any suggestions would help me a great deal! i would like to set this gun up for some steel matches...

FS/FT M&P40 PRO! WITH EXTRAS 650 AND AMMO Selling my used M&P40 PRO i am the original owner.. included are: -3 full size factory!!! s&w magazines -comes with all paper work, original box, lock, and s/m/l backstraps -apex striker block so no grity trigger the firearm is in great shape...