We used to pattern our duty shotguns quarterly along with qualifying with them and our side arms and rifles.

00 Buck is my preference based on seeing bad guys shot with it and going to shooting/homicide scenes.

Ghost Ring sights, side-saddles, 2 3/4" Brenneke slugs, and a Vang Comp'ed barrel is the ticket.
9" patterns of Federal Premuim 00 Buck (2 3/4") @ 25yds, were the norm. Other guys' shotguns preferred Remington ammo. I could keep 8 of the 9 pellets on a Brussels target @ 50 yds if I really paid attention to the sights. 2 1/2" groups @ 100yds with the Brenneke slugs were also the norm.

There's not much you can't kill with a shotgun.

Ed

"Not in an open forum, where truth has less value than opinions, where all opinions are equally welcome regardless of their origins, rationale, inanity, or truth, where opinions are neither of equal value nor decisive." Ken Howell