At some point there needs to be a ethical minimum. I think we all agree. The 22lr can kill a deer just fine, the 22wmr does it fantastically. However the smaller you go the more options you are giving up.
We have the "ethical minimum" in my current home state. It is essentially the .223 Remington and it is the same in every state that I hunt hoofed game in. There is no reason here in 2026 why that shouldn't be the case.
However the smaller you go the more options you are giving up.
I was a licensed and bonded hunting and fishing guide (#2725) in California from 1995 to 2012 and guiding was a full-time occupation for me from the day I left law enforcement in 1996 to 2007.
As a GUIDE, I needed things out of a rifle that I absolutely don't need as a sport hunter, for the very simple reason that if I had to shoot while guiding, I was forced by circumstance to make shots I would happily pass on in my own sport hunting endeavors.
When I started guiding pig hunters, I carried an inherited Griffin and Howe Springfield in good, old-fashioned .30-'06. That worked until it didn't and the instance where it didn't had me shooting stern to stem on a pig intent on crossing a three-tier barbed-wire property boundary fence. He was within yards of it and headed for a live oak thicket between himself and the fence when I fired my first shot. He was deep into that live oak thicket when I pulled my stripper-clip out and closed the bolt on my seventh shot, that finally ended the drama. After that, for my next batch of clients, I used my Ruger No.1 Tropical in .375 Holland and Holland. I kept using that for several years. That thing would absolutely stop a pig on a stern to stem shot, every time, without fail. But it wasn't the best thing going for wounded runners in my hands, so I ended up using a CZ 550 in 9.3 X 62. That would also stop a pig in its tracks on a stern to stem shot, without fail.
As a sport hunter, though, I don't need that kind of heavy artillery that I found useful as a guide, because I'm not taking a shot over 300 yards, I'm not taking a shot on animal that isn't stationary when I pull the trigger, and I'm not taking a shot on an animal that isn't offering me a broadside poke through its heart. That's nothing new. I've operated that way since my first season as a licensed hunter when I was an 11 year old kid in 1976.
Aside from two trips to Newfoundland for caribou and two trips to Botswana, and the pig hunting I do with my in-laws and grandson in Italy, I've never hunted east of the Mississippi River. The longest shot I've made on game as a sport hunter was 278 yards.
I literally can't count the number of California Central Coast pigs I tagged with pipsqueak cartridges like the .250 Savage and the .30-30 Winchester.
I still have my log books from my guide service, so I know how many pigs I saw get shot and killed by clients, shooting everything from the .222 Remington in a Remington Model Seven rifle to the .458 Lott and all of the popular stuff in between. It's over 1,000 pigs over 11 years.
Here's a very unpopular truth: assuming a pig shot in the heart / lung cavity on a broadside presentation, there isn't any substantive difference in the wound channels made by a .223 Remington tipped with proven medium game bullets to "better" cartridges like the .243 Winchester, 6mm Remington, .257 Roberts, .25-;06, .260 Remington, .270 Winchester, or the 7mm-08 Remington. On broadside presentations, any of them get exactly the same result from a vital-zone shot out to 300 yards.
I had a client who wanted to bring his daughter on her first hooved-game hunt. She had a Remington Model Seven in .222 Remington which he said she shot well, but I need not worry, because he was going to trade that rifle in and get her a 7mm-08.........
I had the devil of a time convincing him that his eight year old daughter and I would be a whole lot happier if he just let her give it a try with the rifle she already has. "No, the only pig she'll see isn't going to be beyond the range of a .222 Remington to kill it dead." "No, she's not going to be taking quartering shots under any circumstance." "Yes, I am absolutely good enough to get you, her, and me within 150 yards of a pig." I finally convinced him by saying that if I had to finish what she started, I'd let her try my .250 Savage, which recoils about as much as a .223 in a bolt action does, and if she was okay with that, we'd go out the next day and let her whack another one with that. The kid drilled a 290 pound boar with tusks just shy of 4" through the heart at 82 yards. Predictably, it was a clean kill. Post-mortem revealed the heart was mostly goo.
Some of the kids I guided had deer hunting experience. I could tell them that the vital zone of a wild pig is significantly lower and farther forward in the chest cavity compared to that of a deer, and thus a standard behind-the-shoulder shot that is effective for deer typically results in a missed vital shot or a "gut shot" due to the pig's more compact body and forward shoulder structure, and they would take that to heart. Some of their parents, on the other hand, would nod like they were paying attention and understood, then proceed with a behind-the-shoulder shot when I said "Okay, take him.."
Not only have I seen literally hundreds of examples of what the .223 Remington with proper bullets can do to a pig on a broadside shot that is the vital zone, I've seen what every popular "deer cartridge" does to a pig with white-tail deer shot placement, too. The result is always a whole lot less than immediately lethal. Even a .300 Winchester Magnum won't compensate for gut-shooting.
I started using the .223 Remington for California A-Zone black-tail deer in 1984 and racked up 22 consecutive filled tags with it. When I started using the cartridge, it was not as versatile as I believe it to be today. We didn't have the component bullets or the cannister grade powders back then that combine to make a 5.56 NATO have slightly better "on paper ballistics" than a .250 Savage does at 200 to 300 yards, but we do have them now.
I tagged at least 21 mule deer with the .250 Savage, which absolutely doesn't kill things any deader than my 5.56 NATO hunting loads can, while also not shooting as flat, or being as resistant to wind deflection as the 5.56. It is hard to find ammo and brass for, and with the taper of the case, the brass doesn't last through as many re-loads as LC 5.56 brass does. It also takes about 10 grains more gun-powder to get performance slightly worse on paper than many 5.56 NATO hunting loads have.
I'm not limited in shot options by virtue of hunting deer-sized game with the 5.56 NATO. I use the 5.56 NATO because I limit my shot options to under 300 yards on stationary animals offering a broadside presentation. It kills stuff just as dead, just as fast, as anything else does under the same set of circumstances.