Bolt is stripped. Just seems tighter then I've seen. Haven't taken a brush to the chamber yet. Just swabbed out the chamber. Is it something I should worry about? As long as it goes into battery, shoot it and let it wear in? Or send it back? I've checked the bolt against another barrel and it came out gtg.

As long as it passes the go gauge it should be fine, if you are concerned, then brush the chamber and check again, if it passes again, then start shooting the gun.

Shoot it. If you have poor extraction you know the chamber may be rough or to tight.

I sent a note to the manufacturer and after a few questions they asked for the barrel back. My question is, what could have happened if I shot it? What would a tight chamber do?

Your cartridges might have shown signs of overpressure, but if the go gauge close on it, I suspect it would have loosened up a bit after shooting  the gun, boy as of late, people are sure splitting hairs on things, if the go gauge closes, it is good to go.

How does anybody get a long if they continually question the tools in place to tell us something is okay?

I had a 16" carbine build like that a few years back.

A load that shot/functioned just fine with all my other AR15's would blow primers out of the cases and otherwise cause problems in that one rifle/carbine.

I checked my others till I found a bolt that was a little "loose" in one of the 20" rifles and swapped bolts with the carbine.  No issues since. with either rifle.

Yours might be alright.  If not, you might need to look for another bolt.

If it passes a go gauge I would shoot it. If there are markings on the cases or blown out primers I would look into something else. Lots of good information here!

5.56 and .223 gauges are going to differ and military gauges are unique as well.

There are several chamber specs that meet the definitions of 223/5.56 depending on which manufacturer you are talking to and the intended application for the barrel.

Precision rifles generally have tighter tolerances and are built around specific bullets or within a range of bullets.  

It depends on what you want that barrel to do...if it is a precision rifle, you might want a specific chamber oriented towards that task.

What exactly do you mean by seems tighter?
Are you checking an assembled upper or just the unmounted barrel?
Checking the bolt with another barrel only tells you it works with the other barrel.
Assuming you are not using excessive force a Go gage is a binary result; either it closes or it does not.
Bolts and barrels have tolerances, it is very possible to have a bolt fail in one barrel yet pass in another.
I have had multiple barrels fail the Go gage with one bolt and pass handily with a different bolt.
If a manufacturer asked you to send a barrel back something in the Q&A you have not related in your posts got their attention.

I was checking the barrel unmounted. Bolt stripped. I had too push down on the bolt (quite  a bit) to be able to turn it at all. And then I could feel every lug as it passed over. Then I put the barrel in the upper and hand tightened it. put the bolt in the carrier and tried to put it in battery. You weren't gonna just push it in. I had to give it a good pop with the palm of my hand. Then had to do the same thing to get it out. So technically it did pass GO...But no $200. I'm pretty sure no one here would have been happy with how it felt. Bolt should slide pretty easy into battery.
The only thing the manufacturer ask was whether it was mounted and whos bolt.  I tried the bolt in another barrel because after all it was a new bolt. Why not? If it failed in another barrel I'd know it probably wasn't the new barrel. I was going to ask the manufacturer if I should just shoot it. Then I got the RMA.

That barrel and bolt did NOT pass the GO gauge.  If it took ANY pressure to turn the bolt, it FAILS the GO gauge.  That's why the manufacturer gave you the RMA - the barrel is not properly chambered.

What brand and spec gauge?

Well there ya go. I did not know that. I was told as long as the bolt turns.

SAAMI's spec for minimum headspace in .223 Remington is 1.4636 inches (from the base to the 0.330" datum circle on the shoulder).  PTG, Clymer and Forster GO gauges are ground to this spec.  I've found reference to the actual GI 5.56mm GO gauge being 1.4646", but finding genuine GI gauges isn't particularly easy.  I'll bet OP used a commonly available PTG, Clymer, or Forster gauge.

FedDC, your point is really valid, though a lot of folks here won't quite see it.  A military chamber is supposed to eat any ammo you put in it, while SAAMI's spec is based on bolt action rifles.  That's why the SAAMI spec calls for a short, steep leade, while the military spec has a longer, less steep leade.  But some folks think you have to get a perfectly minimum chamber or you get shafted.  I disagree.  I won't accept a barrel that won't pass a NO GO test, but as long as it passes a GO test, it's not going to be too tight for safety and function.

I have had ONE barrel fail a GO gauge, and I'm very happy I checked it before installing it in an upper.  It was a 300 Blackout barrel made by a well respected barrel company, though one that had only just started making Blackout barrels.  With a bare bolt and my Forster GO gauge I couldn't get the bolt lugs all the way into the barrel extension.  Fine, I thought, I got a bad bolt.  So I stripped down another bolt and got the same result.  I'm stubborn; I tried a third bolt with the same result.  Fortunately the vendor was both a solid guy and aware of problems this maker had had with this caliber.  He gave me a full credit and a discount on a different barrel (CMMG this time), and I only had to wait for the Postal Service to get him the bad barrel for him to ship the new one.  The CMMG barrel gauged perfectly with all the bolts that had failed with the first barrel.

Forster gauge marked  556 NATO
Barrel was marked 556 NATO

The Forster 556 NATO gauge is ground for SAAMI's minimum headspace dimension of 1.4636".  This is important because if the barrel failed with a GI GO gauge, it would be so badly chambered that it wouldn't allow a round to chamber all the way, let alone let the bolt close.  Failing at the SAAMI minimum isn't nearly as bad, even though it is still bad enough to return the barrel.

Measured from the back of the lugs to the bolt face the tolerance range for bolts is .153” to .156”.
Given your description if the bolt measured in at .153” in your position I would have taken them up on their RMA.
At 1.4646” US mil-spec is .001” looser than the SAMMI min spec 1.4636”.
When building a weapon for heavy firing schedules I try to keep the headspace within US mil-spec.

At least you're checking headspace. From my experience, most people DO NOT check headspace, they simply assume everything will be in-spec and blast away. I've only ever seen one KB in person, but it was enough that it made me consider checking very worthwhile on each and every rifle I assemble. I also know guys who will swap one bolt carrier group from gun to gun to gun. I prefer to permanently mate a bolt to an extension, just because that's the way I like it.

It is shocking how few people own gauges.  I bought a set of 10 that measure it from below spec to over spec.  It's a good general guide so that I can determine where in the range it is.  

I have one in 308 and one in 556.  It is comforting to know exactly where a specific chamber falls in the range.

That's what I mean. I've asked people that bring home built guns into the shop if they headspaced it, or not, and sometimes I get a weird look like "WTF does that mean?" or "People actually do that?". Lol. Usually the guys that tell me they wanted to, but didn't, say it was because they didnt want to or know how to remove the ejector. I have a $10 piece of delrin I bought from Brownell's specifically designed for removing the ejector roll pin. Works great.

Yeah, I was shocked the first time someone brought me a messed up AR that they tried to assemble on their kitchen table, holding it with a rag and a C clamp...

First thing I bought back in the day was some basic armorer tools...blocks, punches, screwdrivers, gauges, etc.

Half the people on this site are kitchen table gunsmiths.

That's a low estimate.  Honestly, seeing some of the work "professional" gunsmiths have done, I'd say that a lot of firearms are better off in their owner's hands.


Will a bolt close on a .223 or 5.56 ROUND and NOT CLOSE on the .223 or 5.56 minimum gauge?
(can't a round be used as the gauge?) - assuming it's removed and inspected to make sure it didn't further seat the bullet(?)


Isn't it more telling to have a maximum gauge to do the testing with instead of a minimum gauge (on firearms that are either used or otherwise have operated previously)

Yes, it is possible to be able to close the bolt on a factory round and still not pass a GO gauge check.  SAAMI minimum headspace for cartridges is 1.4596" while the SAAMI minimum chamber headspace is 1.4636".  Here's the SAAMI authoritative document with the specific data.  Go to page 68 (the 80th page in the document) if the link doesn't take you there automatically.

Manufacturers almost always load rounds BELOW SAAMI MINIMUM (cartridge) headspace length.  This avoids problems with customers getting mad because their "ultra precision" (and not technically correctly chambered) rifle won't eat off-the-shelf ammunition.  

So NO!  A loaded round CANNOT be used to test for minimum safe chamber depth.

Used guns probably don't need to have a GO gauge check...but I stress the "probably."

Got tired of taking my builds to the GS and paying $45. I figured if its something that should be checked...I should know how to check it myself. And this was my 1st.
Hence the drama.
I asked my GS if it was really necessary on a new build. He said no...in a perfect world...

I have measured a number of bolts and found them all over the tolerance range.
If a barrel manufacturer sets the barrel extension so the barrel will pass a Go gage with a bolt high in the tolerance range then when matched to a bolt low in the tolerance range the headspace could be two or three thousands past minimum.
So, probably to keep headspace tight, we wind up with barrels from some sources that will pass Go with one bolt yet fail with another.
If your barrel fails the Go gage you don’t know if it just a little off or significantly off.
The headspace specs are designed to insure a maximum tolerance cartridge works in a minimum tolerance chamber.
As was previously noted factory ammo is typically manufactured to be less than maximum tolerance.
So a person could put a lot of rounds downrange and not know he had a potential problem.