I am new to this K-80 business and have a lot to learn. On the O/U barrel which I prefer for singles, the under barrel has a POI of 15" with the comb at the lowest position. Nothing wrong with that but I have to raise the comb when I shoot the unsingle barrel to get the same POI. I understand the POI on the O/U set can be changed with barrel hangars. Can someone please explain. Thanks, Rich