converting an AR from 5.56 to 6.8?


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jlg
March 16, 2011, 07:27 PM
I have a 5.56 AR-15. I want a 6.8 AR-15. Can I just swap barrels? Or do I need to change anything else? BCG, buffer,...?

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Mudinyeri
March 16, 2011, 07:33 PM
Nope, can't just switch barrels. It might be most convenient to get a complete 6.8 upper that way you can just pull the two takedown pins, trade uppers and go shoot.

TonyAngel
March 17, 2011, 02:43 AM
assuming that you can do the work, swap the barrel, bolt and mags. Of course, that will leave you with a barrel, bolt and mags that you are no longer using. I'd just get/build another upper. Really, the barrel and bolt are the high cost items. The upper doesn't cost but about $100 plus whatever handguards you want to throw on.

rbernie
March 17, 2011, 07:29 AM
Nope, can't just switch barrels.Sure you can - it just takes about $75 in tools and a bench vice. :) But I know what you meant - the conversion is more than just unsnapping bits. You have to either physically deconstruct and reconstruct the upper or replace the upper itself.

As stated - the barrel, bolt, and magazines are the unique bits that make the rifle shoot either 5.56 or 6.8 or whatever.

madcratebuilder
March 17, 2011, 07:51 AM
You may be money ahead if you buy a complete 6.8 upper and then sell your 5.56 upper.

68wj
March 17, 2011, 09:24 AM
I have a 5.56 AR-15. I want a 6.8 AR-15. Can I just swap barrels? Or do I need to change anything else? BCG, buffer,...?
Assuming that you have the knowledge and tools to swap the barrel (including muzzle device), that is the only step requiring anything beyond basic field stripping. The bolt itself must be swapped as well, but the remainder of the carrier is the same. After that, load up your 6.8 magazines (CProducts if you can find them since the company went "under", PRI, or Barrett. D&H coming soon).

If you consider yourself a "blaster," you may want to hold onto the 5.56 and have 2 uppers. The 6.8 is priced relatively equal to quality hunting or target ammo, but cheap plinking loads do not exist. Handloading is a major plus for this caliber.

jlg
March 17, 2011, 09:54 AM
Thank you everyone. I have two 5.56 uppers and was debating either selling one or just converting it. I really like them both but don't need two and I want a 6.8 to hunt with.

I've put one of my uppers on the Trading Post. http://www.thehighroad.org/showthread.php?t=581407

It's a very nice shorty with a 12.5" Compass Lake Engineering Douglas Barrel on a VLTOR upper if anyone is interested.
http://a4.sphotos.ak.fbcdn.net/photos-ak-ash1/v2362/39/61/528032963/n528032963_1357195_6931694.jpg

Thanks again

Omaha-BeenGlockin
March 17, 2011, 10:00 AM
2 uppers?

That means you need to build another lower.

Mudinyeri
March 17, 2011, 10:02 AM
Sure you can - it just takes about $75 in tools and a bench vice. :) But I know what you meant - the conversion is more than just unsnapping bits. You have to either physically deconstruct and reconstruct the upper or replace the upper itself.

As stated - the barrel, bolt, and magazines are the unique bits that make the rifle shoot either 5.56 or 6.8 or whatever.
Well ... technically, yes, you can just change the barrel, but if you don't also change your BCG you're going to have some problems.

Since he has two 5.56 uppers and doesn't want/need both, I'd say the OP is headed in the right direction.

TonyAngel
March 17, 2011, 04:51 PM
He doesn't need to change the BCG. He only needs to swap the bolt.

Hey, that's a nice upper you're selling. It has some nice doodads on it. Why not consider just picking up a WOA 6.8 barrel for around $300 and spending another $100 or so on the bolt and do the swap. With what you'll lose selling your used upper and what a new 6.8 upper costs, you may wind up ahead just doing the barrel swap.

jlg
March 17, 2011, 04:56 PM
Hey, that's a nice upper you're selling. It has some nice doodads on it. Why not consider just picking up a WOA 6.8 barrel for around $300 and spending another $100 or so on the bolt and do the swap. With what you'll lose selling your used upper and what a new 6.8 upper costs, you may wind up ahead just doing the barrel swap.

That was my thinking. Just didn't know if it was possible or how easy it would be.

TonyAngel
March 17, 2011, 05:52 PM
Well, I'm not super familiar with that upper setup that you have on there and am not real sure about how it all comes apart; but on a "standard" AR, a barrel swap is a 20 or 30 minute job. What I mean by "standard" is that the handguard is attached to the barrel nut, which comes off with a standard barrel wrench. Swapping barrels is really easy, if you have the tools and know how to do it.

rjrivero
March 18, 2011, 12:33 AM
Consider picking up a .300 BLK barrel. Same bolt, same magazines as a .223/5.56 just a different barrel. The 308 cal bullets can be had in a variety of different weights for a variety of different needs.

220gr bullets going 1050fps or 123gr bullets doing 2315fps out of a 16" barrel. The 123gr bullets get really good comparisons to the 6.8......

www.300aacblackout.com

MyOpinion
March 18, 2011, 01:14 AM
I am a fan of White Oak also. You may want to talk to John Hollliger about some of the other calibers he works with. Some are based on the 6.8 case renecked to a few other chamberings. 6WOA comes to mind and there are some called PDK I think.

jlg
March 18, 2011, 10:24 AM
I've actually kicked around the thought of a 300 BLK. But for now I want a rifle primarily for hunting. Down the road I may build a really short 300BLK (or similar) for primarily subsonic use...but subsonics don't work too well for hunting and the 6.8 definitely outshines the 300 BLK in the supersonic category.

Tirod
March 18, 2011, 10:50 AM
Check ARPerformance for their Socom barrel package, which includes the bolt, cam pin, and firing pin.

It does NOT require an armorer's tool set to work on. If it's an A3 upper, it can be clamped down any number of ways to secure it firmly against unscrewing the barrel nut. I used a set of Bessey vice blocks in my bench vise holding the rail and lower surface sideways.

Here's the secret to getting the nut off or torquing it on - if you are confident in your ability and the quality of tool, a set of 12" channel locks will do the job. It's not rocket science, you only tighten it enough to line up the sprocket and insert the gas tube. Loosening it seems to be the bigger challenge, and if you are willing to hazard a few nicks on a hidden part, go for it.

If that's too much risk, buy the special tools, be advised there is no guarantee it won't slip, either. It's still up to the user's level of competence, some folks can break a hammer.

Barrel, bolt, magazine, ammo is all you need.

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