I've used both IC and Mod chokes while shooting 3-Gun matches and I've never had a problem either knocking down steel or breaking static clays. Since you're more or less aiming the gun like a rifle in that kind of shooting, I don't think it makes much difference how much choke you use.
"I am the sum of all evil...yet many still seek me out; a green jewel they must possess. But see how I destroy their lives."
- The Loc-Nar