Yes. Under circumstances that have a measure of control the .223 is adequate for deer that are lung/heart area shot with some bullet weights and barrel twist rates so that the bullet is traveling at a minimum of 1800 to 2000 fps to mushroom and deliver 1000 ft-lbs at impact, a guideline that has been used by many. Using the Matunas Optimal Game Weight Formula (OGW) formula V³x W² x 1.5 x 10 ‾¹²  where a (60 g)² bullet traveling at (3100 fps)³ has an OGW of 160 pounds at the Muzzle but at 100 yards the deer size is closer to 125 pounds.

For those folks that are shooting AR models in .223 you may want a slower twist rate barrel to shoot heavier bullets like the 60 grain with a higher Sectional Density. I prefer a caliber with a higher Sectional Density where the bullet weight and diameter have been documented more clearly as adequate in kill charts.

The above data is not a rule, it is a guide and is subjective.

If you want to hunt with your AR for deer just know that shot placement is even more critical. The .223 is not recommended by me for big deer as in Northeast Whitetail above 150 pounds which is the norm for a small Northeast Buck. I would choose a 6 MM/.243 caliber or larger if given the option before using a .223. But that is just me…