Unmarked AR barrel.

drifter dave

drifter dave

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So I picked up a used 10.5 barrel on the EE, its supposed to be a 5.56 NEA.
Unfortunately there are no markings on it anywhere. NEA says that even their 1st gen are marked. Can a gunsmith easily confirm a 5.56 chamber before I shoot Nato through this thing?
 
drifter dave said:
So I picked up a used 10.5 barrel on the EE, its supposed to be a 5.56 NEA.
Unfortunately there are no markings on it anywhere. NEA says that even their 1st gen are marked. Can a gunsmith easily confirm a 5.56 chamber before I shoot Nato through this thing?
Click to expand...

So good news then, it's not an NEA barrel :stirthepot2:

You don't need a gunsmith to verify the chamber just a set of 223 go/no go gauges and a 5.56 no go gauge.
 
09outlander said:
So good news then, it's not an NEA barrel :stirthepot2:

You don't need a gunsmith to verify the chamber just a set of 223 go/no go gauges and a 5.56 no go gauge.
Click to expand...

Seeing as it's just the throat that's different, wouldn't you need a throat gauge and not a standard chamber gauge?
 
223v556.jpg
09outlander said:
Nope, it's not just the throat that's different.
Click to expand...
 
In the above diagram, the salient point (IMO) is the freebore of the 556 vs the 223. The higher pressure cartridge bullet is given a little more jump before engaging the rifling.

Your gunsmith can tell. Me, if I didn't have gauges, which I do, I'd just shoot it and examine my primers for pressure signs. 99.999% chance a modern construction 10.5" AR barrel doesn't have a tight 223 REM chamber in it, regardless even if it is marked 223 REM.
 
ARMS EAST said:
In the above diagram, the salient point (IMO) is the freebore of the 556 vs the 223. The higher pressure cartridge bullet is given a little more jump before engaging the rifling.

Your gunsmith can tell. Me, if I didn't have gauges, which I do, I'd just shoot it and examine my primers for pressure signs. 99.999% chance a modern construction 10.5" AR barrel doesn't have a tight 223 REM chamber in it, regardless even if it is marked 223 REM.
Click to expand...

Agreed, almost all AR barrels are 5.56 and those that aren't will most likely be 223 Wylde. It's very rare to find a true .223 chamber in an AR barrel, some may be marked 223 but that's usually just to get around US export BS. Just watch for pressure signs whenever you try a new type of ammo.
If you're really that worried find someone to borrow the go/no go gauges from.
 
Ideally, to check the freebore/throat angle you need a gauge that looks like this

556_223-04.jpg







.............or just fire some 5.56 in it and if it doesn't blow up you're good ;)
 
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Think. We are making a big deal abount not much.
Pretty hard to screw up an ar bbl, that said we have done it at times.
Just instal and shot it.
If it is an AR bbls from nea, it is one of there better products.
Bbb
 
tactical_tech said:
I would imagine it could be confirmed with a set of GO NO GO gauges.
Click to expand...

And I can confirm you don't know what you are talking about. Imagining technical details is a very bad idea.

The only difference between 223 and 556 is the length of the throat. A headspace gauge datums on the case shoulder and never comes anywhere near the throat. The only way to confirm a 556 chamber is the cast the thing and include the throat. Then you need a shadow graph to compare the casting to a reamer. I'd bet only 1 or 2 smiths in the entire country have that kind of equipment.

Of course the OP could just not worry about it and shoot whatever ammo through it like hundreds of thousands of us did before the internets came along.
 
Suputin said:
And I can confirm you don't know what you are talking about. Imagining technical details is a very bad idea.

The only difference between 223 and 556 is the length of the throat. A headspace gauge datums on the case shoulder and never comes anywhere near the throat. The only way to confirm a 556 chamber is the cast the thing and include the throat. Then you need a shadow graph to compare the casting to a reamer. I'd bet only 1 or 2 smiths in the entire country have that kind of equipment.

Of course the OP could just not worry about it and shoot whatever ammo through it like hundreds of thousands of us did before the internets came along.
Click to expand...

Interesting, now I know.
 
Suputin said:
Of course the OP could just not worry about it and shoot whatever ammo through it like hundreds of thousands of us did before the internets came along.
Click to expand...

Exactly :d

Just catch a couple of your empties and inspect them for pressure signs. You should do that with any ammo you shoot from any barrel anyway. The internet has made us worry about sh!t we really don't need to put so much thought into.
 
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Can you post a couple pictures of the barrel? I may be able to tell you if it is NEA from the profile and seeing the pictures. Many NEA barrels were not marked but they didn't make 223 chambers...just 556.

Ryan
 
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