Originally Posted by JonM
You need to do that with the optic mount not the irons themselves
I am a dummy sometimes and dislexic at best. I have shot the AR for many years but never tried to do what I am doing now, having a holo sight and a back up iron.
Today, I got to thinking, (scary) but I measued my original A2 sight, and my new Back up. My back up needs to be lower not higher. However I am going to correct this, by not jacking up the holo sight, but installing a extended post front sight. It is in fact 1/8 of an inch longer, and will get me co-witnessed, with out any riser.
Now having said that, I am betting that I will have my dot on the holo, a bit down into the raised front sight post. I will still see the target, but not an optimal situation. So if this proves to be true, I will put a 4 sided gas block, replacing the front sight, and get a flip up front sight.
To me absolute co-witness just seems correct. Anything less, is putting in a guessing game.