AR caliber confusion - So many choices

Hey AR owners,

I have been looking around online and trying to research some AR options and it’s pretty obvious… There is a TON.

I am fairly new to USCCA and the AR world. I am only in my early 20’s and have only fired two AR’s with only a handful of rounds each, not even a full mag. I am in the process of becoming a LEO in the Midwest. I have never been lucky enough to go hunting, but am really hoping to get the chance going forward and going a lot in the coming years. Hunt for really anything; deer, hogs, or other medium game.

I say all of that to ask for a little help in distinguishing some caliber options to avoid and some to really lean into and study. I highly value home defense and as stated above I want to be able to hunt. I want a solid AR caliber that works great for all. I have done quite a bit of research on multiple calibers lately and do understand that I could always fall back on the standard .223/5.56. I just fell like I want something else more for the hunting aspect and I want to be able to reach out a little further.

A little I have learned so far:
– .224 Valkyrie sounds great in theory, great range and ok energy out at some crazy high distance numbers. But it has too many problems still with the rounds that they are separating from the jackets as they travel down the barrel and I am not changing barrels after 2000 rounds like is typical.

– 6.8 SPC is possibly the new US Military round, but it seems many people think it is a step down compared to the 6.5 Grendel. Also, the ammunition seems to be hard to get and you need to make sure the barrel is a 6.8 SPC II or the tolerances aren’t good. Just seems a hard choice being it is so new, but it could pop off and really flood the market if the military does go with it.

– 6.5 Grendel sounds really good so far for what I am seeing. Really solid round and lot of powder behind it and some really solid numbers for reaching out to 400 yds with a standard 18" barrel setup and lots more energy at those farther ranges than these other calibers.

– 300 Blackout sounds to be more of an AR pistol and close quarters round. Not really looking at something like that.

I am really just looking for a bit of discussion on this and maybe some feedback as to if I am looking at some of my findings correctly. I would like to stay at a decent price point for a rifle, building or buying one is a totally different discussion for a later day. Really just looking for discussion on calibers.

Anyone who has multiple AR’s or lots of experience with them, is it a good idea just going for a bigger round right away or should someone fairly green like me just get a .223/5.56 to start?



Welcome to the Community, @GodsWarriorII! Glad to have you here!

There is SO much to learn when it comes to ARs and all firearms! I recently just built my first AR and it was a blast (pun intended).

I’ll let the caliber gurus jump in and answer the caliber question.

I do have a curiosity question for you - if you’re on your way to becoming a LEO, why an AR instead of a handgun for home defense? :thinking:


Thanks for the welcome. This is my first activity in the community so kind of a big topic to start into!

I already have a S&W handgun. Also have a 22 rifle for plinking and training friends and family with. I bought the handgun, had it for about 2 months and then joined the USCCA. Not looking for a new handgun caliber, just need to find a great AR caliber. Need to start building a little arsenal. Need to get my wife a handgun and then get an AR for any situation.

I see the reason of having a gun that fulfills many purposes/roles. That is why I would like to find a gun that suits the most purpose in one cartridge and I can work it hard in many ways. I also think that an AR would be something I would grab first in the night, but for now it is the handgun I grab all the time.

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Welcome @GodsWarriorII,

I’m not sure of all places but I do believe a great many jurisdictions frown on 5.56, or .223 for hunting purposes. Will let those with more knowledge jump on that.

What sort of ranges will you be shooting for hunting? You typically get longer ranges in the Midwest than you do here in the South.

A home defense gun and hunting gun are a hard combo to come up with due to over penetration. But for hunting I’ve used .308 to great effect and a friend’s 6.5 Creedmore.

Now me, personally, I am a fan of the .300 Blackout.
But you are likely to get as many different answers as you are people. In other words. Your Mileage May Vary.


Is a font of knowledge on AR in general and Calibre’s specifically.

Secret :chipmunk: edit: my .308 is on an AR-10 platform

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As referenced above some places do not allow a .224 bullet for hunting big game (rabbits may be ok).
You are also missing a ton of other calibers, if you want to go down that route.
.50 Beowolf
.450 Bushmaster
and on and on.

As for the 6.8SPC and military trials… those died out about 10 years or more ago. Actually not a bad round for inside of 400m.

I do own a 6.5 Grendel and I hunt with it too. I know quite a few others that hunt with it as well.

Be aware that larger cases, such as .308 and 6.5 Creed etc take a different lower/upper than the smaller 5.56 standard.

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I am expanding my AR collection.

Started with my Ruger556, got my VR80 (12ga in AR style) my AR10, just got 1 AR pistols with 2nd on the way (bit longer barrel than the first), next on the list will either be a 300 blackout or Beowulf and I just asked my gun shop to put 2 more lowers in the pipeline.

350 legend. It is a straight wall cartridge, designed for midwestern deer hunting where bottle neck round are not allowed. The capacity is only slightly less than 5.56. Rounds aren’t expensive. And, the lower is the same as a standard 5.56/.223 platform. Change the upper, and toss in a standard AR mag, and you are good to go with 5.56 ammo.


5.56 is going to be cheaper to shoot. If this is your first AR you are likely going to want to put a lot of rounds through it getting up to speed on the new toy. Those other calibers all have their strong points, I love 6.5 Creedmoor) but the price compared to 5.56 is going to be a factor.

The AR platform (both AR-15 and AR-10) make for great hunting rifles that transition nicely to Home - D and Zombie guns. Your Gov’t and mine spent a lot of time and $$$ making me proficient in their use. I see no reason to not use that ability other than it is not a conventional Walnut and Blue Steel “hunting rifle”.

For ease of use the more “conventional” calibers are a go to option. I hunted this year with an AR-47 with Hornady “Black” ammo. I haven’t had the opportunity to start reloading in 7.62 X 39 yet as the rifle is new to me. Essentially it has enough “Oomph” to take a VA deer out to about 300 yards (based on the 1000 FTLBS rule and also fit’s in my half second rule ((in that if it takes the boolet more than a half second to get there I’m not shooting game with it at that range)) Practice ammo is fairly cheap and similar in weight/velocity performance to the high end stuff.

I had a 6.8 SPCII upper and found the boolet performance lacking at distance.

300 Blackout is a neat round to play with on the subsonic scale with a suppressor but in general falls flat after 150 yards.

I’ve not played with the 6.5 Grendel but have a friend that has one and he states with a well placed boolet it will drop a deer inside 300 yards.

On the AR - 10 platform I still like the 308 and a 178 AMAX and have no issues out to 500 yards

The 6.5 Creedmore is certainly a viable option but I also believe in mass for critters, for steel and paper it’s fine.

If I really wanted to max out performance I would be sniffing around the 7-08 as the boolet flight characteristics of the 7mm are top shelf inside 1K yards while looking at heavies.

AR’s are Lego’s for big kids. You can try new stuff on the cheap and swap things around just keep your pistols and your rifles separate.



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My 2 cents. Go with the AR-10 in .308, it has been around since 1954 and is a proven man stopper and game getter. Stick with the common calibers. :wink:

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I would say, start out with the typical 5.56/.223 caliber. Your costs for ammo will be the lowest, and there is an abundance of ammunition choices at all weights for hunting/defense. There are so many good choices for defensive rounds. I’m not familiar with hunting laws in your state, but if it’s allowed the heavier 62-77gr rounds (SMK, TMK, Gold Dot/Fusion) have great reputation on game like smaller deer and hogs.

I don’t know much about the other variations like .224, 6.5/6.8 Creedmore/Grendel.

I know a little about 300blackout. Because the powder burns so quick, you can get most of it’s potential in a really short barrel. Somewhere around 8-9" of barrel burns most of the powder. You do gain a bit more velocity out of a 16" barrel (if you don’t want to go pistol route, possibly legal/hunting issues), but not as much difference as you do with 5.56/.223. The best hunting round for 300Blackout is the 110gr Barnes TAC-TX which is outright devastating and built specifically for 300BO, but it’s over $1.50/rnd. Hornady has a really good 110gr VMAX which is (IIRC) a .308 varmint bullet, repurposed for 300BO (slower velocity) but it’s more of a fragmenter. The VMAX is also a really good choice for home defense because of less risk of over-penetration compared to the Barnes. It usually sells for ~ $0.70-80/rnd, but they were selling for a little while 200rnd loose in a little ammo can for about $0.50/rnd, not sure if that’s still available.

300BO will for sure, be more expensive to shoot. The cheapest factory ammo for range/plinking is going to be near $0.50/rnd unless you reload your own ammo. The really awesome thing about 300BO is the only thing that is different compared to 5.56/.223 is the barrel. Everything else is the same.

I would also say, maybe have a look at the AR-10 platform (running .308) which should be good legally for hunting everywhere and will take down most (all?) game in the lower 48 states at really extended distances. You have a lot of variety in ammunition choices, and the cost is reasonable because it’s such a popular and common caliber.


Here is my .02 worth. I started deer hunting in Wisconsin when I was 14 with 30 30 Winchester. When my brother was old enough he got the 30 30 and I graduated to a 223 bolt action. (All rifles were owned by my dad).

The 223 did not have the knock down power of the 30 30 but it shot a lot flatter at a longer distance and if you used it for squirrel or rabbit there would be something left. If I were going to buy my first AR and wanted to use it for both hunting and home defense (based on the information you provided) I would go with the AR15 chambered in 5.56.

Ammo will be a bit cheaper for range time and it is also something my wife could pick up and use without any difficulty. What I mean by that is I would not worry about the recoil for her (my wife has never been over 120 lbs. even when she was expecting). It is easy to handle and fun to shoot, I would not use it for bear or moose but I dont think that is what you are planning on hunting.

One last thing about the 556/223, I was in the army for 8 years and never missed a 300 meter target with open sights (not sure I could do it every time now as my eyes are getting old).

No matter what you choose the best advice I can give is get out to the range as often as your budget and schedule allows.


Lots of great feedback and comments everyone. Really appreciate it.

Especially so soon! I didn’t expect to get so many responses so fast on here as this was my first post and real use of the page.


Welcome, GW.
I have several ARs. I have 3 .223s, 1 6.5 Grendel, and 2 .308s.
the 223s are great for general shooting. Cheap, accurate, and can double for varmint guns.
The 6.5 Grendel is my wife’s hunting rifle. She has successfully taken hogs and mule deer with 1 shot kills.
The 308s are AR10 platforms, and personally, my favorite hunting rifles.
I would not hunt deer with a 223 when there are so many better options for stopping. As Elmer Keith said, “use enough gun.”
ARs are like Barbies for guys. You can accessorize! I’d recommend starting out with .223. Get one, shoot it alot, take an armorers course, learn how to customize it the way you like. WARNING–you will never get back the money you put in one. That said, when I shoot my AR with the LH receiver and Geissel trigger and realize how much better it shoots with an upgraded trigger (first thing you should do), it’s all rainbows and unicorns.