In the front of my career, the outfit issued #4B, 27 pellet load. They finally had an agency shooting or two and the results were pretty dismal, due to range and clothing, the #4B pellets did not penetrate well at all. I also listened to a very sober lecture from an agent (not sure of agency) who shot a perp twice w/ #4B on the border and got drilled by .30 carbine himself. He went down (obviously survived) and the perp went back across the border to escape w/ unknown results.
Those episodes spawned a number of unoffical field tests against car doors, winter coats, you name it by staff, resulting in discussion, and to my knoweldege the general abandonment of #4B by Fed agencies, at least the land management outfits. OOB or slugs is now approved ammo for duty shotguns and has been since the late '80's.