.223 is legal in Texas, as is ANY centerfire rifle. .204, .17 Rem., .25-20, .30 Carbine... Lots of cartridges that are less appropriate than a .223. But, that's all irrelevant, since the guy asking the question is from Louisiana. What is legal in Louisiana?

I agree that it is smaller than what I would use (I use a .243 Win., and there are fruit-loops out there who say it is too small as well), but, if state law says it's legal, then that state's Parks & Wildlife Service has made the decision on ethics. .223 is legal here in Texas. I subscribe to Texas Trophy Hunters Magazine, and EVERY month they publish photos of deer killed with various .22 caliber rifles. Of course, our deer are not nearly as heavy as the deer from some other states, and in those states, the Parks & Wildlife Service has probably set a higher "minimum".

The "ethics" question does NOT apply to legal caliber/cartridge. Rather, it applies to things like choice of properly constructed bullet and limitations to range and shot selection that are within the caliber/cartridge's performance limitations.

Note: There's a guy over in the Guns forum who has posted about numerous one shot deer kills with a .22 Hornet. It's all about bullet selection and shot placement... I'd say a guy who chooses his shots, hits accurately, and makes clean one shot kills with a .223 is a helluva lot MORE ETHICAL than some clown who goes out and buys the latest whiz-bang super magnum deer slayer cartridge, but can't hit the broad side of a barn with it and ends up gut shooting deer due to the severe flinch he developed because of the rifle's noise and recoil...