I can only offer up my experience with hunting with the AR platform. A few years back, I decided to build an AR as a dedicated night time hunting rig. Essentially, I was looking for a rifle that would allow me a quick follow up shot if needed. Originally, I wanted to build it in 22-250. For some reason, it became a hassle to build it around the 22-250 caliber, so I settled on the .223.
I will say that some of my decisions I made on the build made the AR heavier than I would've liked. I chose a 22-inch barrel and went for a fixed stock, instead of the lighter adjustable stock.
I've been hunting predators for over 20-years and this was my first AR build. My usual go-to rifles are chambered in 204 and 22-250. I call my 22-250 Thumper because whatever I hit, dies where it stands. I've found the 204 equally as deadly, and If I do my job, the critters usually die where they stand out to 200-yards.
Once the AR was finished, I decided to hunt with it during a season. I killed seven coyotes and three bobcat with the rifle. I was using 55 grain rounds.
Using the AR: Two of the coyotes were shot within 40-yards and died where they stood. The rest, took a bullet right behind the shoulder (80-150 yards away)and took off, dying 100-yards from where they were first hit. Two bobcats were dropped at 60-yards and died where they stood. The third, hit at 100-yards at night, took off and died 200-yards from where he was perfectly hit.
My conclusion, and this has nothing to do with the AR platform, but I feel the .223 wasn't giving me the knock down power I was used to with the 204 and the 22-250. This of course is no knock on the AR platform, but I did find the rifle too heavy for what I wanted to use it for (probably my fault). Also, putting the rifle in battery (hitting the bolt release) was way too loud for night hunting and calling in general.
Lastly, I never did need it for a quick follow up shot...the original reason I built the rifle.
Just my two cents.