Oldjarhead
New member
I have a AR-15 with a fixed standard A frame front sight post. I recently purchased a Holosun hs503gu red dot sight for it. It has a 1/3 co-witness riser. How much difference will be the bullet point of impact in the 1/3 co-witness configuration which the dot and reticle are slightly higher than the front sight post at say one hundred yards? First time doing this. Thanks.