Jame, you may remember from your other post that I said I love my CZ 527 Heavy Varmint in .223. With the right load it's a tack driver.
The others have pretty well covered the range end and bullet usage. So here's a little different twist on your inquiry. You had mentioned hunting in your other post.
The difference between .223 and .308. .223 will take anything from squirrel and rabbet (head shots if want to eat them) up to "small" deer and pig. I shy away using it from deer and larger pigs. That's where the .308 comes in. .308 is good for wolf size animals to "probably" close range, 100 yards or less Moos. I may get corrected on the moos size animal. That's where the 30/06 comes into it's own. Wolf, deer, elk, moos, bear 30-06. There are overlaps between all the calibers and people will argue what should be used for what. .223 shines for varmints.
If you want long range range rifle go .308.
527 Heavy Varmint.
Yes, I always manage to pull one.