Co-witnessing would be a good thing. On the guns that I have red dots on (all of which I have yet to shoot), it seems that in order to get the dot to line up with the factory iron sights that I have to bring the gun into an uncomfortable angle with the muzzle feeling like it's very low. I "zeroed" my dots with the use of a bore sight laser so I "think" they're right, but I can't be sure yet.
Anyone else find this phenomena to be true for them? Or am I just way off with my zero?