I know .223 will kill deer. I've done it before. Also on hogs.

I just have one simple question - how far would you be willing to shoot a full sized (175 pounds and under) deer with a 20"  AR15?

The deer I have killed have all been under 50 yards.  Reason I'm asking is I love hunting with ARs but just put up some stands that would require longer shots (0-250 yards).  I know the limitations of the round and have a 100% recovery rate.

I'm starting to look into building a 6.8 just to have and retire the .223s on deer. But, when its all said and done, a 6.8 AR15 will set me back 800 after the glass and upper get bought

So, simple question - how far would you feel comfortable shooting a 20" AR15 on a mature whitetail deer? 1:7 twist. Name your bullet, name your distance, name your shot.

I'm feeling really nervous extending past 100 which is why I'm considering the 6.8

maybe not the answer you want to hear, but I just faced the same set of decisions this year myself.  I have hunted with AR's for years and have done well.  But, most shots were right around 100 yards or so and I was usually able to take neck shots---drt and no problems.  When I couldn't, a shot behind the shoulder into the vitals also equaled dead deer. Then last year, I lost a deer.  I had poor shot placement (for 223 bullet) and had bullet failure.  Hit square on the front shoulder and the bullet failed to penetrate much past the bone.    I found the bullet jacket laying on the ground about 200 yards into the blood trailing….just as the blood trail disappeared.   Things happen and flukey things happen.   I would still take shots with heavier 223 bullets out to 150 yards with a 20inch AR and I will probably hunt again with my 223 AR.  Buuuuuuut……………..I built me a 6.8 upper for this year…...

I think you are on the right track with a 100 yard limit.  I might stretch that to 125 or so, but that's all.

I normally hunt with a 260, 308 or 30-06.  Most of my shots are 100-125 yards or so.  Under decent conditions I would consider shots to an absolute maximum of 300 yards.  I'd prefer to be closer.  Beyond that the variables are too great.  If I flub the shot a bit, any of these three cartridges still have enough power to make for a clean kill.  A liver shot deer isn't going to go too far when the liver is obliterated for example.

The .223 can cleaning kill deer, but there isn't a large margin of error. if that shot is flubbed somewhat, its a bigger, more important issue with 223.  In addition, those longer range shots are harder:  Wind drift is significantly greater with little .224" diameter bullets, meaning your are more likely to flub the shot that you might be using a 260, 7mm08 etc.  A 223 isn't the ideal tool for long range deer hunting.

6.8 would be an improvement.  I hate to stir the pot up, but your best choice for retained energy and killing power "at distance" is likely the 6.5 Grendel.

correct me if im wrong, but from my limited research, 6.8 is a fine cartridge out to 300

The 6.8 is a fine cartridge.  It's beginning to get 'stretched' at 300.

There are published velocities and claims.  Like ALL marketing data, its 'embellished".  Maybe that box says the muzzle velocity is 2700 fps.  In my experience, they usually use longer-than-normal test barrels, say a 24", to plump those numbers up.  And the bullet manufacturers like to make sure their ballistic coefficient numbers are "optimistic" too.

Doubletap makes a 6.8 load with a barnes tsx 110 at a published 2710 FPS.  That is impressive.  IF (emphasis on if) it gets 2710, then that bullet strikes with 920 ft/lbs of energy at 300 yards.  Certainly 'enough', and just under the often recommend 1000 ft/lbs for deer.  It should get it done, but we are back into the category of "not a ton of room for error". And this is with one of the 'hotter' available loads.   If, however, that published MV is optimistic, you'll get less energy.  A slightly lower actual MV, and maybe an error in range estimation, and we're rapidly dropping into the 800 ft/lbs of energy category.  Again , its enough, but it doesn't have a great margin for error.  You are using the cartridge at it effective limit.  Essentially, at those longer ranges, the 6.8 is delivering actual terminal numbers (800-850 Ft/lbs)  that closely resemble the 30-30 Win at those same ranges....  And fairly few people think the 30-30 is a 300 yard gun.

If you are willing to either be selective at 300 yards, or better yet, keep shots closer to 200-250, you'll see a market improvement in performance.  Remember, the 6.8 is a great cartridge and one certainly MUCH better suited to deer hunting than any 5.56, but it still was designed as a close quarters cartridge,  

My take:  If you want vastly increased performance from an AR platform on deer to moderate ranges (out to 200) the 6.8 makes a ton of sense.  If you habitually want to shoot deer at longer ranges, you're going to want something that drives a heavier, longer, more streamline bullet to higher speeds, and you're into traditional cartridges like .260, 7mm08, .270, etc...

Long story short - the 6.8 is a vast improvement over any 5/56 if you want to hunt deer with an AR.  If you really want to hunt deer at longer ranges, the AR (traditional, chambered in 5.56, 6.8, 6.5) isn't the best tool.

What bullet are you going to use? I have not killed one with a .223/5.56 since the newer bullits came on the scene but I think the newer bonded stuff would let me strech it out past my normal limit of one hundred . Killed them in the olden days with 69gn smk because though I thought 223 was on the light side for deer I wanted to hunt with my AR and figured heavy was better. Bullit construction came into play on a doe at six yards when I forgot my offset and hit the top of the sternum-strait on chest shot- with what turned out to be a crap load from a local manufacturer. The action did not cycle fully and a double feed ensued. The pill deflected into the right sholder, mostly, with full seperation of the jacket. Her windpipe was blown out and major vessels were severed so she died fast anyway but not as fast as as the one I shot twelve hours prior with the same setup at forty that dropped like a sack of concrete.

I have some of the Winchester Razorbacks that I plan to try next year if I use 223-planning to build a 300blk for my primary though. That's the plan anyways, if I was wanting to strech things out in a standard 223 sized AR I'd consider the 6.8 but probably build a 6.5. With the 300 I plan to keep it down to 100 or so, maybe a bit more if I go with a carbine length bbl over a pistol/sbr bbl.

With 62-64 grain bonded bullets I would take that shot at 200 yards and in.

Well, I fo'ed with a 6.8

I shoot a 16" barreled Stag in 6.8spc and my handloaded 110gr Sierra Pro-Hunters clock 2300fps. Silver State Ammo with the same bullet gets 2500+ with the same bullets.

Last year I shot a spike buck [that dressed out 120lbs] at a measured 185yds. It was walking up a hayfield into a stiff wind and that little bullet shattered the brisket, wrecked the lungs, and was found under the skin of the offside shoulder. The deer went about 40yds and died.


So I would have no issues with a 200yd shot with that gun and load. The .223 is another matter.

Probably twice as far as you can make a correct range estimate or a correct wind call.

I have three one shot kills between 250 and 350 with a 16" bull barrel and 62 grain Federal bonded.

Small deer? 350yds?