Know someone who's shotgun shoots a circular pattern. Very few shots in the center of the pattern. What might cause this? He shoots factory ammunition.

Overchoked

Yep, what he said. Classic sign of a busted pattern from too tight a choke. Tighter is not always better with shotgun chokes. Went through this exact same thing with one of my shotguns recently. Backed out to a .670 constriction and patterns improved dramatically.

If not overchoked, is he shooting at a large sheet of paper? If his POI is off, you'll never know it unless you are looking at a large target, say a 3' x 3' sheet.

I knew it had to be the barrel or the choke. So thank you for your thoughts. Dont know what choke he has but will research further.