home
At the front of my career, the agency, along with a number of other Federal outfits as well, had #4B described by policy as the approved buck load. About mid career, that got changed, again, along with most other outfits, to OO buck. If one was going to load a PATROL gun with buck, OO buck would be it for me.
The #4B was not much of a penetrator. I watched a full size car door take a load at about 15-20 yds, perpendicular to the shooter, at a training session (1984-85?), window up, and not a pellet made it through, and about half did not even make it through the outer sheet metal. There were also reports that heavy winter clothing was limiting penetration as well at longish shotgun ranges too. All that, and the fact that we were not issued carbines at the time, convinced me to load my shotgun with slugs for patrol work in the #4B years.
But for a HOME gun, used in the interior, garage, driveway (?), against threats exposed and wearing temperate clothing, I think #4B would work just fine. One of my house guns is so loaded. As I expect it my be grabbed for use against a marauding coyote as well, that added pattern density is a plus, as OO B gets very thin from open chokes much past 20 yds.
I've wondered about the hevi shot T buck as well, but the stuff is expensive and not available (to best of my knoweledge) in 2.75" shells.