6.8 Upper and 5.56/.223 Lower Compatibility

D

Doublea A

New member
Hello wise men and women.

I have a Daniel Defense M4 (.223/556) and was wondering whether the Daniel Defense 6.8 upper will be compatible with .223/5.56 lower?

If YES! How about the "magazine well" and bolt carrier group? Do I need a different one or the .223/5.56 will work?

And the last question is what are people’s feelings about the 6.8 round in terms of hunting anything under 600 lbs and its availability now and in the future? All suggestions are welcome.

Thank you.
 
I am no expert but the lower should work, but you would need a different bolt, and magazines.
I have been looking at the ballistics which come in just above the 7.62X39 and just below the 30-30. I think hunting bullets would open up well at these velocities but not fly apart leading me to believe it could be a very good deer cartridge out to 250 meters and good on hogs at up to 200.
 
The new upper will work fine, and as dvdcrr says, you will need mags and BCG (which should come with the upper.)

I really came close to getting a 6.8 upper for my LRB lower... I just didn't want another caliber to load for. I think it's head and shoulders above the 5.56mm... just not plentiful (ammo and components.)
 
The upper is a direct swap. You well need magazines and at minimum a bolt if not a complete BCG. A complete BCG is the best option, that makes a plug and play swap.
 
6.8 is a great round! Mine has been flawless. When I bought it, ammo was mail order only,(thus my excuse to reload for it), now you'll find it is sitting on the shelves.
 
Bolt, barrel, and magazine are all that's different.

As for 500 pound game, as said, the ballistics are in between X39 and .30-30, although typical fps is higher with the lighter bullets most shoot. Obviously, hunting 500 pound game with a .30-30 means less than 200 yards, in the 6.8, you'd still have way over 1000 foot pounds of dispatch.

If any caution was advised, it really is specific to the game and it's anatomy. Heavy boned animals or with tougher hides would need better shot placement. Good shooters have been knocking down elk at over 400m with this size category. And bad shooters have lost game with larger guns at much closer ranges. There can't be a blanket recommendation.
 
yes, they're compatible.

you will need a new bcg (just best to keep the two uppers completely separate) and magazine.

6.8 is a very fine round for hunting at 250 yards or less using a 16" barrel carbine.
 
Doublea A, let me assure you, the 6.8 upper, as a caliber, is compatable with an AR-15 lower. You mention "magazine well". Let me explain.

The AR-15 lower is designed for cartridges with an overall length of equal too or less than a standard 5.56 round. Hence, 6.8 SPC, 6.5 Grendel, .204, .30 RAR, and plenty more all fit. Where there may be some fit issues is if your upper or lower is slightly out of spec. I have an Olympic Arms 6.8 SPC upper mounted on a DTI lower that requires a punch and slight taps to seat/remove the rear pin. Since you are sticking with DD on both products, I would not expect that.

Caliber incompatibility begins with the .308 length cartridges. The AR-10, LR308, LAR-8, SR-25 (whatever you want to call it since some are sensitive to blanket label the AR built into these markets with the moniker AR-10) use a larger magazine well and larger magazines to accomodate the longer overall length of the .308 parent family of cartridges (.243, .260, 7mm-08, .338 Federal) as well as the 6.5 Creedmore.

The bolt inside the bolt carrier is a different one compared to 5.56. You will need a new bolt at a minimum, or if you want to make it easy (but more costly) an entire bolt carrier group.

The magazines do have a different follower in them for 6.8 than 5.56.

As far as ammo availability, the companies I discovered that cater to the 6.8 round are Hornady (loads with VMAX and SST bullets), Silver State Armory (have many different bullet selections), Sellier and Bellot (use a 110 gr polymer tip), and Remington (have FMC and Trophy Bonded Core Lokt). There are probably others, but those are the ones I am aware of.

Another source of 6.8 information is a website called "6.8 Forums". You will find a lot of dedicated information on the cartridge as well as AR's built for them.

Good luck on your purchase!
 
You can swap a .50Beowulf directly. As long as the 6.8 upper doesn't have crazy milling on the upper it oughta be a direct swap. 6.8 was designed to fit in 5.56NATO mags, so I doubt you'll even need new mags.
 
@ insomini: .50 Beowolf? Where'd that come from?:confused:

The magazines are the same between 5.56 and 6.8, but the 6.8 uses a different follower based on looking at the military 5.56 and different 6.8 mags I have. And you'd expect that, the body of the cartridges themselves are different diameters.

Not sure if you would get any FTF issues if you utilized the 5.56 follower in the mag compared to 6.8. I've never tried it. Not certain why you'd want to. Just buy some followers, take apart the magazine, put in new follower.
 
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