Question on short chambered AR barrels

[fjruple]

I believe we will need some additional information on your barrel.

1) Did the barrel come with the barrel extension installed? If yes, generally these barrels are headspaced by the manufacturer unless one slipped through.

2) What is the chambering, length and twist on the barrel? .223 Rem, 5.56mm or 5.56mm NATO, 1/7. 1/9, 1/12, 1/14, gain twist, etc.

3) Is your chamber or bore chrome lined? It gets difficult to finish ream a chamber that is chromed plated.

4) Was the barrel advertised or marked as short chambered? I have heard of match barrels coming in short chambered, generally these are sold to gunsmiths who are building match rifles for a customer.

If the barrel is one that was short chambered you can rent a finishing reamer to get the proper headspacing. I would highly recommend renting a set of headspace guage as well to ensure the headspacing is proper. Kept in mind that 5.56mm NATO has a chamber pressure of about 60,000 psi.

Cheers

--fjruple

[tiriaq]

Thanks for the information. The reason I wondered about the cost is I could buy an other barrel, with a correct chamber for less than having it done. I tries 3 different bolts and had the same result-no lock up. Thanks again.

I'd love to see it myself but if three bolts don't close...there's something wrong...

I bought a finished barrel from a well known Canadian maker. Required selective assembly to get correct headspace; a well used bolt was fine, none of my newer bolts would close on a GO gauge. Almost invariably, AR barrels from competent makers are within spec.

[browningautorifle]

I'll bet it wouldn't take much to sort though, this one we speak of here. Wish it was even on my side of the border... Yes chrome bore will definitely curtail chamber mods. I've heard of short chambered barrels, just not finished AR barrels being short.

[Garvus]

The barrel was complete with the front sight assembly installed with barrel nut etc. I have been thinking that the gas tube may be out of spec and may be a hair to long, I'll pull it and see if that is the problem. Thanks for the replays I'll post if the tube is the problem or not. I had never run across a short chambered barrel in 4 previous builds.

[browningautorifle]

It sounds like it's something simple...wish I was within arms length to look at it. Sometimes having the second guy look shows you it was something simple, like you suggest.