Unmarked Upper….?

[flint stonez]

Anybody ever run into an AR upper without any markings? Trying to help a guy figure out what he has. I know it was purchased just after the Clinton attempted ban (mid 1990’s) It has a heavy target barrel and the carry handle is attached. There are zero and I mean absolutely No Markings of any kind anywhere on the upper. I’ve looked under the furniture and even inside. It is mounted on an old school Colt lower. The owner told me he had it built 30ish years ago so he doesn’t remember who did it. He did say that he knew it was an off brand upper on a Colt lower. He’s Not a “gun guy” so that’s all the information he knows.
Any help would be appreciated

 

[actaeon277]

bump for info

 

[edwea]

I've got one with no visible forge marks anywhere also. Came on an upper I bought for parts that was either destitute or poverty level on the chart.
It still sits in a drawer unused. I guess I'll grab some .

 

[Kirk Freeman]

IIRC very first Eagles were unmarked.

 

[flint stonez]

So let me ask this …. How do you tell if it’s chambered for 223 or 5.56? And how is the twist rate determined? It’s frustrating.

 

[INP8riot]

I'll let someone else speak to chambering but maybe run a push rod through with a brush or patch and mark your rod to know when a full rotation has taken place and then measure how much rod went through?

 

[Nugget]

How do you tell if it’s chambered for 223 or 5.56?

 

[edwea]

The chambering should be stamped on the barrel, maybe the twist as well.

 

[flint stonez]

The chambering should be stamped on the barrel, maybe the twist as well.

I agree 100%. The information “should” be stamped on the barrel. Problem is that neither is stamped anywhere on the barrel and I’ve looked at every square inch several times.

 

[BGDave]

Maybe Nesard or Sendra, Yes, I know they are the same folks.

 

[AndreusMaximus]

How far have you gone in looking for markings? This question may be unhelpful, and is coming from a place of complete ignorance, but I can't help but wonder if there's any chance that for some weird reason the barrel would have markings that are covered by the barrel nut/receiver, and could only be seen if fully disassembled. That would be super weird, but it's also odd to not have any indications at all as to what it's chambered in. My understanding is that the differences between 223 and 5.56 chambers are only a matter of a few hundredths or even thousandths of an inch here or there, something that would be extremely difficult to determine by taking measurements anywhere.

 

[BigMoose]

I mean.. if your really that worried.. the only way to know for sure is a barrel slug and a chamber cast.




At the very least you could do a simple headspace test.

 

[flint stonez]

How far have you gone in looking for markings? This question may be unhelpful, and is coming from a place of complete ignorance, but I can't help but wonder if there's any chance that for some weird reason the barrel would have markings that are covered by the barrel nut/receiver, and could only be seen if fully disassembled. That would be super weird, but it's also odd to not have any indications at all as to what it's chambered in. My understanding is that the differences between 223 and 5.56 chambers are only a matter of a few hundredths or even thousandths of an inch here or there, something that would be extremely difficult to determine by taking measurements anywhere.

I have stripped everything off the barrel that could even possibly cover any information with No success.

Correct me if I’m wrong but to my knowledge it’s safe to fire 223 in a 5.56 firearm but 5.56 in a 223 is Not recommended.

 

[AndreusMaximus]

I mean.. if your really that worried.. the only way to know for sure is a barrel slug and a chamber cast.




At the very least you could do a simple headspace test.

Would a chamber cast let you determine if it's 223 vs 5.56? It seems to me like the differences would be too small for a chamber cast to give you enough precision to even measure them, but I really don't know.

 

[AndreusMaximus]

I have stripped everything off the barrel that could even possibly cover any information with No success.

Correct me if I’m wrong but to my knowledge it’s safe to fire 223 in a 5.56 firearm but 5.56 in a 223 is Not recommended.

Ah, okay, got it. I thought maybe you had only taken off the handguard, but left the barrel attached to the receiver.

And, yes, that is my understanding as well about 223 vs 5.56. If you determine that it is definitely one of those two, I have no idea how you'd tell which of the two it is, but you can always play it safe and treat it like a 223 barrel, because 223 is safe to shoot through a 5.56 barrel, but not necessarily vice versa.

 

[BigMoose]

Would a chamber cast let you determine if it's 223 vs 5.56? It seems to me like the differences would be too small for a chamber cast to give you enough precision to even measure them, but I really don't know.

It gives you an exact cast, so if you take your Micrometer on the cast, you should be able to figure it out.

But a set of headspace gauges would probably be enough. I am more worried that something unmarked could even be something other then 5.56/.223 so I went with a chamber cast sugestion.

 

[AndreusMaximus]

It gives you an exact cast, so if you take your Micrometer on the cast, you should be able to figure it out.

But a set of headspace gauges would probably be enough. I am more worried that something unmarked could even be something other then 5.56/.223 so I went with a chamber cast sugestion.

Ah, I see, that makes sense. Thanks!

 

[indyblue]

One reply related to this issue over on ar15.com mentions if it is a chrome lined barrel it is likely ok for 5.56.

Is the barrel chrome lined? If it's chrome lined, its a good bet its ok for full power "5.56" ammo, since the SAAMI .223 chamber doesn't really work with chrome.

New bare barrels are cheap enough, I'd say just buy a new quality 5.56 barrel if in doubt or treat it as .223 only.

 

[flint stonez]

It was built in the mid 90’s so I’d bet it is either 5.56 or 223. Were there other calibers available 30 years ago?

Really great information. I appreciate everyone’s input helping me.

 

[Leo]

The no name asian stuff that was seen advertised in Shotgun News was often unmarked. Kind of a crap shoot with quality, but they were cheap.

The Saami spec drawings for both are on the internet and a Stoney Point chamber gauge set up and a quality caliper goes a long way. A chamber casting is best if you know how to measure it up.

There will always be an exception, but the only true .223 chambers I have ever measured were on 1 in 12 or 1 in 14 twist barrels. Those were on rifles from the 1970's.

I thought everyone measured barrel twist with a brush on a cleaning rod with a piece of tape as a flag stuck 12 inches out. Easy and effective.

the old school quick check was to take a live round. get a bunch of candle soot on the bullet and chamber it. If the barrel lands did not smudge off the soot, it was assumed you have enough leede in the chamber.