I dunno ....
Just starting to "get back into shotguns" after a few years hiatus & patterned some 00 buck in a couple 12s a coupla days ago.
Fairly amazing that you can get whatever you want by just going through the motions, picking various loads & shooting them through various shotguns.
Tried 3X various flavors of "cheap" 00 buck through 2X shotguns & got a really tremendous variety of patterns at 25 yards.
After "getting back into shotguns," I find the old truisms absolutely factual = you have to pattern any specific load in whatever shotgun/choke you want to use to get any kind of a reality check on anything.
Of the (9 pellet) 00 buck, I got patterns of 2-3+ FEET! at 25 yards using IC & Mod ... not something I'd really write home about. I did not get what I wanted outa these ....
I switched to a Fed #4 buck 3" (41 pellets of #4 buck), mod choke
& got a pattern of ~1.5' = much nicer & about as close to a .22 cal machine gun as you can get. That'll work for only one shotgun .... stopped by The Store on the way home & picked up a 25 count box of 27 pellet #4 buck in 2-3/4 that'll shoot out of every 12 I own. We will see .....
Slugs are very effective, but at the same time, I'd like to find a goodly buck load to 25 yds.
Unless attempting to shoot through very heavy stuff, I do like #4 buck due to its more numerous pellets &, so far, seems to pattern better - outa mine.
There's no question that any 00 load, at 10-15 yards will do the trick = the pattern will be "tight enough" against a man-sized target. Thing is, at that range, so will most any other size shot charge as well.
.... still looking for that very special buckshot load for my 12s ....