Just remember that POI can be changed by different cartridge loadings and also by the way a gun is held by the shooter. As I understand it, the barrels are regulated in such a way that they actually cross a very short distance in front of the muzzle. The flex of the gun when shot supposedly moves the crossing point out to a distance approximating 40 yards or so. This refers to horizontal POI. I'm not sure how vertical is affected, if any, by these factors.

John McCain is my war hero.