No Go fail

[Mtneer]

I'm working on my 2nd AR build. My first one used an assembled upper but this time I wanted to do it all myself. Decent parts (Aero Enhanced upper, PSA Premium BCG, Brownell 10.5" barrel). Everything went well, I thought.


Bought a Go/No Go set to make sure things are right (didn't arrive until after I assembled). It passed the Go check. But the BCG is flush on the No Go.

So now what? Anything I should check on my assembly? Go to gunsmith? Send barrel back to Brownells?

[20X11]

Not necessarily the barrels fault... could be the bolt.

[ray1970]

5.56 or .223?

There is a difference in allowable headspace between the two.

I’ve had 5.56 chambers that would close on a 223 no-go gauge but were within tolerance.

[Great-Kazoo]

Which HS gauges you using, chamber 223 or 5.56? Is the closing a loose fit or tight? The real question is does it close on a field gauge, if not depending on the gauges used it's (IMO) usable as it. I've had more than 1 factory / mfg complete upper as well as rifle, close on a NO-GO gauge. I stopped using the forster ones switching to with Manson, which made a difference on what was closing or not with the No-Go

[Frac]

So now what? Anything I should check on my assembly? Go to gunsmith? Send barrel back to Brownells?

Did you remove the ejector and extractor from the bolt before testing headspace? If not, then re-check after removing them.

Check the things others have mentioned, like verifying you have 5.56 gauges in a 5.56 chamber.

If it does indeed fail headspace with a matching gauge, then you can test around a little bit. Swap bolts between your two rifles and test again. Does the problem follow the bolt or stay with the barrel?