For out to 150ish yds on deer I wouldnt hesitate to use a holographic red dot, especially the models with selectible Dots/reticles. I have 2, they are on my turkey guns (835UM & 870SM) & I shoot the 3.5" THUNDEROUS mega heavy, cross your eye Nitro loads so I know they'll hold up to any 3" slugs/buckshot loads! Either a simple Weaver style bridge type mount that bolts atop a ribbed barrel or a saddle mount & you are good to go for not alot of chee$e!