Why? Also how often do you actually get follow up shots?

Never owned both at the same time but I think it matters on what type of hunting you are doing.

When I had my AR-10 it would be a sit and wait type hunt. Had a RRA with 24" BB, dude weighed a ton, and I couldnt carry it around the woods all night. So back then if I knew I was doing spot and stalks I would carry my Tikka 25-06. Now if I would of had a light weight 16" barrel 308 I might of gone with that.

I now hunt with a 16" 556 and carry it all the time. Light weight and accurate but with poor shot placement I have lost several hogs.

Edit: As far as follow up shots, never got the chance with AR10 unless I was 400-500 yards away and I missed on the first

556 given the right environment all the time, its just hitting them when they are running circles around you in the woods that gets me

What optic? The one time I had a .308 I tried to stand and shoot a deer and 6-8 shots later the deer kept running.

When I built the 308 I put something big on it, its been a few years, but I made it for long range. It definitely added some weight to the already heavy gun.

The 556 is a cheap 3-12 by Bushnell, I keep meaning to replace it, but I beat the hell out of that gun and it never looses its zero, so why change a good thing. It doesnt do great in low light though, but is clear as day the rest of the time so I am letting it ride for now. I dont baby my 556, it sees rain, mud, etc. Kinda impressed me so I guess thats why I use it as my go to gun.

One thing though, I never use 556 for deer hunting. Only hogs. I have a designated deer rifle that I use.

Last year all I used was my 308. This year im carrying my 223. Chances on a solid follow up shot are kinda slim.

I use my 20" POF 308 with a SWFA 10x SS scope for still hunting, and my 16" custom AR with aimpont T1 for stalking around. It's soon to be a SBR to make it even more mobile.

Killed 2 bucks this year. 1 at 85 yards with AR15, ran 100 yards with heart shot. 2 nd at 258 yards with LR-308 , 1 shot into the neck ran 50 yards second shot double lung and dropped . It's all about distance and bullet selection.

223 my animals don't run

I hunt with a .223 with a Primary Arms red dot. No magnification at the moment. I have have taken follow up shots. I recently shot a deer at about 75yrds. I put one in the lungs and it took off and I put another in the neck.

It's not really a question of do you get follow up shots since most animals you shoot at, even when you hit them, they will most likely run. It's more a matter of can you pull off a safe, accurate follow up shot to the kill zone and not in the guts.

A 223 is basically a 200 yd light Varmit cartridge not even remotely in the same category as a .308. It will take hogs or deer with proper shot placement or luck but so will a 22 LR. I'd have no problem with using it on deer or hogs with good projectiles, but not on wall hanger expensive hunts. The .308 loaded at 2800 FPS with a 150 Barnes TTSX is at least twice the cartridge and good to at least 450 yds.

Neither for a dedicated hunting AR, 6.8
I don't like AR10s for hunting as they are heavy.

Only once have I taken a follow up with a .223 AR and it was on my buck of a lifetime. He showed up while I was yote hunting and I took a heart/lung shot at 110 yds. He turned the opposite side to me and I hit him again in the heart and he dropped. Dressed out he had no heart muscle left and only one lung. All my hogs have gone down with a single neck shot and never did more than quiver. My .223 is a "target of opportunity" gun. When I'm in the stand for deer it's a 7.62x39 upper. Three one shot kills in three years on heart shot deer, no follow up needed.

If I'm actually hunting, a 5.56 is almost useless for me, because it is too big for rabbit and squirrel, but too small for deer and pigs. For me, a 5.56 is strictly for punching holes in paper. For that I actually prefer a .22LR though.

I have a .223, a .308 and a 300 Blackout. I like all three and use them based on the game. Predators and hogs I like a .223 at 100 yards or so. Hogs alone and at possibly longer distances, I prefer my .308, and for predator or hog in closer spaces less than 100 yards, I love the 300 Blackout because I get a .30 cal bullet that impacts likes a hammer at 2100 FPS in a smaller package with a 16" barrel.

I actually split the difference and built 2 6.8's on the AR platform. Enough punch for deer and hogs comfortably to 300 yards. Has about 7-10 lbs less recoil than a 7mm 08 makes it a good fit for my 8 year old to use. I built them with an adjustable stocks just for that purpose.

I use my AR-10 w/ big glass on it for sit and wait hunt like East.

my 5.56 and 300BLK (I alternate) w/ aimpoints go w/ me riding around type hunting and/or at night (for hogs, obviously I don't shoot deer at night)

as for follow up shots I have had them w/ both. had a big group of pigs come by the stand and opened up on them w/ the .308 (FNAR at the time) knocked a couple down, running shot is pretty difficult w/ bigger glass i will say, much easier w/ the AR-15s w/ aimpoints.

I am sure I am offending those who love it, but I wouldn't give a nickle for the 5.56 or .223 cartridge as a hunting round. I've used it with miserable results on hogs. I have too much respect for deer to even try.
Before you say I can't shoot, I am 3 for 3 dropping hogs in their tracks since I began carrying my .308 and shooting from the same position ( a measured 120 yd shot).

You cant shoot

beat me to it, I'll killed plenty of deer with 5.56. but if your not comfortable with it, don't try it.

Maybe it was just the ammo you were using.. A good hunting round out of a AR will put a pig dead right there. I don't know about deer, because I don't hunt deer. I just shoot SS109 62gr steel core penetrator at hogs. Is probably the worst possible round for hunting because it is supposed to penetrate not expand. I don't really care how many times I have to shoot hogs, I hate the creatures.. They still work fine though.

The AR that I use most is my 6.8 SPC - great hunting round!

I use my 5.56 but will use my 308 once the suppressor comes in.