HavasuMike Posted October 7, 2016 Report Posted October 7, 2016 I thought I was done. I got the barrel a couple days ago and was ready to finish. When I tested the head space, the bolt closed on the NoGo. Today I borrowed my friends bcg and the same thing happened. I emailed Faxon, but have not heard back from them. The barrel is the 20", Heavy Fluted, .308 WIN, Rifle-Length, 416-R Stainless Steel QPQ. The web page says DPMS LR-308. The bcg is Aim Surplus AIM .308/7.62x51 BDG NiB Bolt Carrier Group. Their web page says DPMS pattern. Since this is my first 308 build, I'm totally confused. I am now assuming that I need a different bcg. Any thoughts?
survivalshop Posted October 7, 2016 Report Posted October 7, 2016 (edited) Contact your barrel manufacturer as you have done & send them your Bolt & Barrel , they are good to work with . One other thing , I have seen bad Head space Gages before here & I would use another set , before sending anything back. Edited October 7, 2016 by survivalshop
HavasuMike Posted October 7, 2016 Author Report Posted October 7, 2016 Just heard from Faxon. It sounds like they will take care of the problem (whatever it is). Waiting to hear about the next step.
survivalshop Posted October 8, 2016 Report Posted October 8, 2016 Have you tried a different NoGo Gage ? Or take it to a GunSmith & let him use their's , if you can't find another known good Gage set.
98Z5V Posted October 8, 2016 Report Posted October 8, 2016 Did you chamber that gauge like you'd chamber a live round? Bolt locked back, insert gauge (either into the chamber or via magazine feed), then release the bolt catch?...
survivalshop Posted October 13, 2016 Report Posted October 13, 2016 On 10/8/2016 at 4:07 PM, 98Z5V said: Did you chamber that gauge like you'd chamber a live round? Bolt locked back, insert gauge (either into the chamber or via magazine feed), then release the bolt catch?... I surely hope not , ouch .
98Z5V Posted October 13, 2016 Report Posted October 13, 2016 That's the one thing I can think of that will make a No Go gauge close on a good barrel... only reason I asked...
survivalshop Posted October 14, 2016 Report Posted October 14, 2016 Or a out of spec Gage to begin with .
HavasuMike Posted January 8, 2017 Author Report Posted January 8, 2017 Sent the barrel and bcg to Faxon. They checked it and said it was good to go. They asked if the go/nogo was a "match" set. The packaging said that it was so I returned them. Don't know what the difference is between match and not match. Maybe someone that knows about this stuff can explain. Anyway, I finally got it put together and fired a few rounds. Every thing seemed to work fine. Now I will add a scope to see how it shoots. Thanks to Faxon for their help.
Flabbergasted Posted January 11, 2017 Report Posted January 11, 2017 I'm having the exact same problem with my build as well. My gauges are labled "Match" too. If I may ask what brand of gauges did you use?
Jetdoc Posted February 14, 2017 Report Posted February 14, 2017 Gents, I have a observation regarding HS on AR type barrels. Lets assume you do have a Ar barrel that is out of limits. The only way I see to correct is to adjust the barrel extension with shims. if that were done wouldn't your gas port be out of alignment , meaning it would not be at the 12 o'clock position. I ask because every AR barrel Ive had checked by a PGS has been good to go ......Just my two cents.
blue109 Posted February 14, 2017 Report Posted February 14, 2017 (edited) The barrel doesn't rotate, the barrel nut does. Shims to correct a headspace issue would need to be ridiculously thin. No way you could make them durable. Edit...Re-reading this it looks like you mean shimming between the extension and barrel? That would require the barrel to twist I suppose, but I'd guess the same issue would apply. Edited February 14, 2017 by blue109
survivalshop Posted February 15, 2017 Report Posted February 15, 2017 (edited) Shims wouldn't help , AR Barrels Head Space is determined by the Barrels Chamber & Barrel's Extension Locking Lugs . Barrels Gas Port is the last thing installed after HS has been determined & set.( If installing an A2 ,Tapered Pin Front Sight , that would be the last thing after Gas Port installed ). Head space is measured from Bolt face , but Barrel Extension determines that . Edited February 15, 2017 by survivalshop
Jetdoc Posted February 15, 2017 Report Posted February 15, 2017 13 hours ago, survivalshop said: Shims wouldn't help , AR Barrels Head Space is determined by the Barrels Chamber & Barrel's Extension Locking Lugs . Barrels Gas Port is the last thing installed after HS has been determined & set.( If installing an A2 ,Tapered Pin Front Sight , that would be the last thing after Gas Port installed ). Head space is measured from Bolt face , but Barrel Extension determines that . I believe you answered my concern , if the head spacing is set/confirmed before the gas port is drilled then every AR type barrel is set, confirmed by QC at the manufacturer. Meaning that when the consumer has HS checked by a LGS hes just doing that for a extra safety check .
blue109 Posted February 15, 2017 Report Posted February 15, 2017 I have never checked a 5.56 gun, and only buy reputable 5.56 barrels/bolts. 308s are another story. No standard means headspace can vary by manufacturer. You are pretty safe buying from the big guys, but there are ALOT of small operations making 308 parts
survivalshop Posted February 15, 2017 Report Posted February 15, 2017 For most builders , it would be wise to purchase a Head Spaced Bolt with the Barrel you order or Purchase . I don't trust a some of Barrel makers any more , its the House hold name ones you can believe the Barrels are properly Head Spaced , still good to check . Also some Coatings on some Bolts have seen issues with hindering or causing HS to be off , even though the Barrel Maker's HS is correct from the Factory .
Jetdoc Posted February 16, 2017 Report Posted February 16, 2017 Thanks for your responses Gents. Ill keep doing what Im doing, its cheaper than a hospital bill.
FaxonNathan Posted February 22, 2017 Report Posted February 22, 2017 Our pleasure to help. As many have ascertained, it can be difficult to match headspacing on .308 weapon. With no definitive universal spec, we took to publishing what headspace bolt we look for and guarantee headspace with bolts that meet these dimensions: http://faxonfirearms.com/blog/technical-interface-documents-faxon-barrels/ Hope this helps!
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