What chamber and barrel twist. I only know one person who hunts deer with a 223 remington.
They have a 1/7 twist barreled bolt gun. Shoots from a fixed position and generally same distance across the field of 150-200 yards. Last I heard he still uses a Sierra gameking soft point. Mind you he is a very very good shooter. Had some expensive German scope and his set up fits his needs.
Growing up the 22-250 was about as "small" as anyone I knew would use. The reason behind big heavy bullets is to make a not so good shot more effective. Miss the kill zone with a light bullet and you just have a wounded deer.
Good thing is expansion had come a long way in bullet technology. Retaining most of their mass and still penetrating.
With that said I was at a farm stand when a man dragged a coyote out of the treeline.
I was amazed at the damage his round did. Claims a 180 yard shot.purpose built 16" varmint AR using nosler factory ammo 60grain varmint orange tip. Hit the coyote right front shoulder and blew out the lower left side. He was the property owner and says he has to thin out the coyote every few years. I asked for permission to hunt or join him. no sorry is all he said.
I should have mentioned that my AR15 has an 18" barrel with a 1 in 7" twist. I have used 65 grain Sierra Game Kings and killed 4 deer with them, but have hit small branches and they exploded and made me miss two deer. The deer I killed were in a field and the two I missed was in hard woods. I'm thinking that maybe I should use my 30-06 in the hard woods.
Correct worded that a bit poorly. I didn't really mean "smaller or smallest" I should have mentioned velocity.
60 grain 22-250 can be pushed to 3500fps or so vs 3000fps.
A missed shot is a missed shot regardless.