I think that the numbers are relative for those barrels, though. A #4 for my barrels may not shoot the same as a #4 for your barrels (I have two Kolars that shoot the same for me; one has a #5 front hanger and the other has a #4); each of us moving down or up 1 number will have the same effect though. Definitely best to double check with Kolar, in my opinion, to make sure you're going to get the result you want if changing hangers.If the number is higher the gun shoots lower. I have a kolar o/u barrel with a #2 hangar and it shoots 90/10. The one I have with a #8 shoots about flat.