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Old February 9, 2020, 12:23 PM   #1
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Deciding on an AR10 caliber..

I've recently gotten the itch to put together an AR10. I have an AR15 and have been wanting to get a semiauto in a heavier caliber more suited for some hunting and the occasional long range shooting. Like many others have done, I am currently debating between going with .308 or 6.5 creedmoor.

I know many on here may jump to .308 for hunting larger game, but I currently have a 30-06 bolt action that I would use for things like elk and other large animals when not archery hunting. I also have a 30-30 for things like whitetail in more compact environments where a higher-power caliber may not be ideal.

Given this, I am stuck on the decision of adding another .30cal rifle to my repertoire (I don't reload just FYI), or adding in 6.5 creedmoor which I view as falling somewhere between my 5.56 and 30-06 that could be used for hunting and also be fun at the range.

I have read that 6.5 creed is more expensive than .308, but much of that information was dated a few years ago and I haven't seen many updates on a price comparison. Budgeting is always a factor for me, so any info on current cost comparisons would be very helpful.

Given my situation and intentions for this rifle, what recommendations do you have?

Thanks in advance.
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Old February 9, 2020, 01:45 PM   #2
T. O'Heir
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Judging strictly by available ammo on Midway, there are far more options with .308. Midway lists 71 flavours of the Creed. 152 in .308. Prices aren't a great deal different.
The only other criteria is that .308 ammo is everywhere. The Creed, probably, is not in smaller places. One of the guys coined the term, 'The Walmart Test'. If the ammo is in your local Wally World, it'll very likely be in all of 'em.
If you shoot much you will be reloading sooner or later. Reloading lets you tailor the ammo to your rifle and is more about the quality of the ammo than saving money. Same bullets for .30-06 and .308. Both love 165 grain hunting bullets. And both will kill any game in North America with a 165.
Oh and a .30-30 is just as, "long legged" as a .30-06. Dangerous out to several miles. Shotguns are for whitetail in "more compact environments". Your bow is the best for that though.
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Old February 11, 2020, 02:16 PM   #3
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You could do either, although for target practice, 6.5 will have less drop and be affected by wind a bit less.

30-30 is just as, "long legged" as a .30-06.
. Physics would disagree.
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Old February 11, 2020, 03:33 PM   #4
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Weight is the primary determinant--if you really are going to use it for hunting--you're going to have a tough time building a "budget" AR 10 that's also light in weight unless you go something like a carbine, which by nature starts cutting into the cartridge's performance.
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I am NOT an expert--I do not have any formal experience or certification in firearms use or testing; use any information I post at your own risk!
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Old February 12, 2020, 04:33 PM   #5
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I suggest the 6.5CM... it truly is that much better in my eyes.

Hunting wise, the 6.5x55 ( basically the ballistic twin of the 6.5CM ) has taken a LOT of critters.. frankly, I think it didn't catch on mostly from the lack of readily available surplus ammo after WWII.

The 6.5CM cheat's the wind very well... and is a great balance cartridge from a Large Frame AR.

To be blunt, I think you will find the 6.5CM very satisfying. Mine have shown very good precision.

The best part is... "if" you end up not liking the 6.5CM, a DIY to .308 barrel swap is super easy.

Or another complete upper will fit right on.

The only holdup I see... is the readily available 308 ammo... surplus 308 is still out there, and some of it is crazy accurate as well, typical priced at around 50 cents a shot.

On a good day... inexpensive 6.5CM ammo is cheapest at around 55cents / rd.. but that blunt nosed S&B 140gr FMJ bullet, while very accurate, is not taking advantage of the BC's of pointier 6.5 bullets... and is "slow" enough to limit it to 100-200 yds range time.

The next closest inexpensive factory round is Horn. AG 140gr... at around 70-80 cents per round... precision is VERY good from my 6.5CM barrels , and its BC is pretty darned good. ( I love this ammo )

Hunting bullets abound for both the 6.5CM and .308.. find one that is precise from your barrel you'll probably be GTG.

The 308 is proven as no slouch.. but, for me the 6.5CM is just enough better, that it is the caliber I reach for in my Large Frame AR's.

And, I gotta say... the satisfaction I get, from my consistently small groups with the 6.5CM pretty much overrides any added cost, ammo wise.
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Old February 12, 2020, 04:57 PM   #6
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I have, and have hunted with several different .308 pattern ARs. My current is a Daniel Defense, and they are pricey. When they offer a 6.5 barrel as a part, I will buy one and switch if over. My .308s are largely for subsonics and shooting Heavy or Mil in competition, but I'd not suggest it for a 3rd or 4th rifle...only maybe when you get to the 30th or so.

The 6.5CM is a little less versatile, but it makes up for it in the long range area. Also, I doubt I ever use a .308 pattern AR, in any caliber, to hunt with again. Heavy is the main reason. I do however hunt with my 6mm and 6.5mm AR15 pattern rifles.

6.5CM over .308 every day of the week except Sundays when I am feeling like a Boomer.
Good Shooting, MarkCO
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Old February 12, 2020, 07:01 PM   #7
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I built my AR10 in .308 simply because I wanted an 18” barrel and I think the creedmore round needs a bit more tube to live up to its potential. Also, where I live .308 ammo is a good bit cheaper.
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Old February 12, 2020, 07:50 PM   #8
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One of my favorite AR10 builds--because it's just all around super reliable and not fussy about ammo and would be murder on game if I had just made in lighter--is a 358 win. This cartridge is undeservedly ignored IMO.
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Old February 12, 2020, 09:22 PM   #9
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An AR 10 in any cartridge is going to be a lot more rifle than I like to carry around while hunting. You will have a hard time keeping it under 10 lbs scoped. For hunting I'd much prefer a trim lightweight accurate bolt gun that weighs 6-7 lbs scoped.

The difference between 6.5 and 308 has been beat to death. I primarily hunted with 30-06 from the 1970's until about 10 years ago. For game smaller than elk it is simply bigger than needed. I chose 308 at the time because it could be used in lighter, trimmer rifles and still do 95% of what a 30-06 would do. And even in lighter rifles recoil was still manageable.

I own 6.5 rifles, but my go-to hunting rifles are still 308. Not that I think 308 is better, but I have money invested in rifles that I like and time invested in developing loads that work in them. At this stage of my life I'm probably not going to start over with another cartridge. The 308 does what I need it to do. The 6.5 is a range toy for me, I still prefer the 308 rifles for hunting because I just like those rifles better.

That said, the 6.5 is the better cartridge and what I'd recommend for someone starting. As a hunting cartridge out to 400 ish yards there isn't enough difference to matter. In fact on paper it can be argued the 308 is a touch better. But not enough to be a game changer. No animal will ever know the difference.

But at longer ranges, especially for punching paper or ringing steel the 6.5 starts pulling away. And most shooters today are punching paper more than hunting.

Ammo is no longer an issue. Yea, 308 offers more options, but you only need 2. Find a hunting load and a target load and what else do you need. Prices are about the same, in fact 6.5 will be a tiny bit cheaper for quality target loads. You can buy 6.5 ammo everywhere now including Walmart.

I handload my ammo but my brother and his son-in-law don't. They buy this locally for $13/box and have shot it sub MOA out to 600 yards. I can get a little more accuracy, but I can't hand load it for this price.
"If you're still doing things the same way you were doing them 10 years ago, you're doing it wrong"

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Old February 13, 2020, 08:19 AM   #10
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I love my 6.5 Creedmore build, it is currently my favorite rifle. I recommend using a JP BCG or at least their extractor and spring. It eliminated 100% of the minor functioning problems I initially had.
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Old February 13, 2020, 09:04 PM   #11
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6.5 creedmoor recoils less, so I read anyway, but if your "long range" isn't exceeding 500 yards then .308 will put more power to the target without any downside - aside from recoil, which is only an issue after a number of punishing shots and not a handful..

Generally speaking most people I see shooting will never see a benefit to 6.5 creedmoor, they are not stretching the range out enough for it to make a difference or running enough rounds where the recoil becomes punishing.
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Old February 15, 2020, 08:54 AM   #12
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For target use:

6.5 has noticeably less recoil than 308 in both semi-auto and bolt action forms. I’d take 6.5 all day, everyday over 308. 6.5 also has less drop and is less effected by wind at pretty much every distance last 100 yds. The only advantage the 308 has is cheaper plinking rounds, but the quality stuff isn’t that different in cost than 308.

Since you have other calibers you use to hunt, I would suggest taking a look at the 6mm Creedmoor as well. I like 308 and 6.5, I like the 6CM even more. For target use it can do pretty much everything the 6.5 can, but it does it with less recoil.

There is a reason the Creedmoors are popular with competition shooters. The 308 is still a solid choice, it just can’t fight drop and drift like the Creedmoors. And it does it all with more recoil.
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Old February 15, 2020, 10:10 AM   #13
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Hey Stagpanther.
I am going to build a 358 upper for an AR and maybe a 338 Federal. In the past I have used metal mags for customers, but I was thinking of using the Mag pull 10 round mag and I am going to use a scallop file to slim down the inner ribs about .040" per side to give better clearance to the case necks where they brace up against the shoulders of the cartridges.
Have you done the same?

In either the 338 or the 358 I believe very good ballistics can be achieved in a shorter barrel because of the room we have to burn powder. My customer wants a 16" and I see no real reason to argue for anything longer. In the 338 Fed I may stick with a 20" or go to an 18"

So my 2nd question for you is in your builds what barrel lengths did you used and did you do any chronographing of the loads?

Please let me know.

AR10 type rifles are not all that popular here in Wyoming and I have suggested the 358 to several people in the past because we have a lot of elk and grizzly bears, but for whatever reason the 2 calibers have not caught on with the auto shooters as much as I would have expected.

I make my own barrels and for a while I made my own handguards and gas tubes because I have found the issue with reliability that was an issue with the 308s and all smaller calibers was more related to port location than most other factors. In the 338s and the 358s it was not a problem because the powder has more room to burn. So I have used standard length tubes and standard barrel dimensions on my 338s and 358s so far, but I have not done the short carbine length on them yet, so this is an area I'd love to talk over with those that have.

Anyway, if you would not mind "talking shop" a bit, please get in touch with me
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