With my camo Remington 870, years back I installed a Leupold Gilmore red dot. It has worked great all these years (about 25!).
I installed an improved cylinder choke tube & sighted in using foster style slugs at 25 yards. When I was happy with that, I replaced the chole tube with an aftermarket tight one & tried my Winchester #5 3" magnum turkey loads on a large sheet with an aiming dot on it. I made sure that the pattern was "centered." Then I shot at turkey neck targets at various ranges to verify effectiveness and to help determine a maximum range for hunting.
It has worked great over the years. I recently purchased a S&W Model 41, 22 LR pistol that came with the exact same red dot Leupold Gilmore sight! Its about a 2 MOA dot and while larger than newer dot models, I'm going to leave it on!