Wonkey Headspace Checks on 1st. LR308 Build

[PasoGunner]

Good morning gentleman,

I’m hoping someone can shed some light on my 1^st issue with my new LR308 Build.

I have quite a dilemma on my hands and I'm just wondering if someone could help me out please. I went to check headspace on my brand new Faxon Firearms .308 Fluted Stainless Steel in Black QPQ coating barrel with my AIM surplus (Faxon recommends these. They use same BCG in test rifles) Nitride BCG. I took out the extractor I also took out the ejector.  I reassembled it and the GO gauge worked perfect. Nice and smooth lockup. . Problem is, is that the NOGO gauge also closed just like the GO gauge. The BCG was flush at back of upper with the GO gauge and NOGO gauge! I also watched the bolt engage the barrel extension lugs. It locks up perfect!! Now I do not have a FIELD gauge, but I'm wondering what you guys would do next. Would you buy the fuel gauge and check it out that way, or would you send it back to the manufacturer? Thanks for all your help I really appreciate it as always.

Also just to check I put the extractor back in the BCG. The Forster Headspace Gauges have the notch for the extractor. I did NOT slam the bolt onto the gauges.

I know RougeNathan at Faxon Firearms will see this thread.

If anyone needs a full spec sheet just let me know.

I am Officially Stumped! Thanks for all your help as Always!!

PasoGunner

Edited June 7, 2015 by PasoGunner

[Robocop1051]

Do you have access to another .308 bcg?

It appears that you did everything right. Either the bcg or the barrel are out of spec...

or both are on the extreme ends of the spectrum... -0.005 on one end and +0.005 on the other.

[PasoGunner]

My father in law may have one. My bro in law does have a functioning rifle. Maybe I can try his.

Do you think it may be safe if it doesn't close on the field gauge? I think I'm grasping at straws. I'm really disappointed. I spent a ton on this build.

Thanks for your help. It's greatly appreciated.

PasoGunner

[guruofhotrod]

Did you get this instruction sheet with your headspace gages?

 

Forster Headspace PDF.pdf

 

As it says in the instructions "If a rifle closes on a NO-Go gage it may have excessive headspace. If a rifle closes on a NO-GO gage, it may still be within the SAAMI Rifle Chamber Tolerance. Next, it should be checked with a FIELD gage."

Edited June 7, 2015 by guruofhotrod

[PasoGunner]

Guru,

Yes I read the directions more than once. I have the field gauge on order. I just thought in the meantime I could try and troubleshoot a little further

[guruofhotrod]

Ya need a different bolt or complete BCG to troubleshoot any further or try your Bolt/BCG in a different barrel/upper assembly - if you were further south,

(I'm just north of the San Fernando Valley) I'd invite you over to swap some parts around to narrow things down.

[PasoGunner]

Guru,

Thanks for the offer and for the great help. I'm gonna go over to father in laws tomorrow and use his brand new AIM BCG. He ordered it quite a while ago so the chance these 2 BCG are from the same lot are pretty small. I have the field gauge on order. Figure I've spent this much may as well keep spending!

[Robocop1051]

Lots of us in the 916 area that can help... if you end up this far

[FaxonNathan]

Good morning gentleman,

I’m hoping someone can shed some light on my 1^st issue with my new LR308 Build.

I have quite a dilemma on my hands and I'm just wondering if someone could help me out please. I went to check headspace on my brand new Faxon Firearms .308 Fluted Stainless Steel in Black QPQ coating barrel with my AIM surplus (Faxon recommends these. They use same BCG in test rifles) Nitride BCG. I took out the extractor I also took out the ejector.  I reassembled it and the GO gauge worked perfect. Nice and smooth lockup. . Problem is, is that the NOGO gauge also closed just like the GO gauge. The BCG was flush at back of upper with the GO gauge and NOGO gauge! I also watched the bolt engage the barrel extension lugs. It locks up perfect!! Now I do not have a FIELD gauge, but I'm wondering what you guys would do next. Would you buy the fuel gauge and check it out that way, or would you send it back to the manufacturer? Thanks for all your help I really appreciate it as always.

Also just to check I put the extractor back in the BCG. The Forster Headspace Gauges have the notch for the extractor. I did NOT slam the bolt onto the gauges.

I know RougeNathan at Faxon Firearms will see this thread.

If anyone needs a full spec sheet just let me know.

I am Officially Stumped! Thanks for all your help as Always!!

PasoGunner

 

Always a pleasure to be of service. 

 

What I can speak to is how we check our barrels. We have a custom bolt machined at the nominal specification that is checked 100% with Clymer gauges. We only allow barrels that pass GO through for sale. 

 

So, assuming the barrel is good (its possible it may not be, but to assume):

1. Your gauges is off. We have seen issues with Forster before. They are not as accurate as Clymer, in our experience. 

2. The bolt is bad (we use AIM internally, but its possible one is on the deep side). 

3. The bolt is within specification, check with field. 

 

Once you get a chance to check with field or another bolt, let me know. We stand behind the barrel 100% and if needed, will get it replaced.

[PasoGunner]

Nathan,

I will be using another AIM bolt to check tomorrow. I will order the Clymer set of all 3. Thanks For THE help. Knowing that Faxon is behind their product makes me feel better.

[survivalshop]

  Is the Chamber a 7.62 x 51 , a hybrid or .308 , it may make a difference with different manufacturers gages . It doesn't take much to make a HS gage useless , we have had at least one here that had a damaged gage set , that gave bad readings . 

[FaxonNathan]

  Is the Chamber a 7.62 x 51 , a hybrid or .308 , it may make a difference with different manufacturers gages . It doesn't take much to make a HS gage useless , we have had at least one here that had a damaged gage set , that gave bad readings . 

 

.308

[PasoGunner]

Thanks Nathan. It is .308. So I bought the Forster GO and NOGO gauges. I guess i should have bought the the field gauge as well.

[survivalshop]

   If your going to get a set of HS gages , get the complete set , its a good idea if you are planing to do a your own work on your rifles . Its like any other tool that is needed to build a rifle or maintain it . 

  I check all the barrels I install by hand , with the Bolt I plan on using , before I install them in AR's .

   I have read & heard of people using the buffer spring close the Bolt on a HS gage , a sure way to potentially damage the Gage .

 

Edited June 9, 2015 by survivalshop

[PasoGunner]

SurvivalShop,

I agree I made a mistake not getting all 3. I should asked what HS gauges Faxon recommended. Well added one piece of Scotch tape (.002) to the back of the NOGO gauge. The bolt would NOT lock up. It's well under MAX SSAMI headspace of 1.640. (So im at 1.636) I gave Faxon my bolt dimensions. I think I'm good to go!

Edited June 9, 2015 by PasoGunner

[FaxonNathan]

Before we get started, we would state that the bolt is good to go, just not nominal. 

We have a couple actual DPMS bolts we use interchangeably and they measure out as follows: 

Lug Depth: .314-.315 
Co-Bore: .122 -.123 

Given this well accounts for the .002" needed to bring you within nominal spec, we would conclude the bolt is out of nominal, but still functional. 

Hope this helps!

[PasoGunner]

*UPDATE*

I CALLED AIM. After letting Joshua know the measurements, he sent me a RMA# and will be swapping out the entire BCG.

Thanks to everyone for their help. I even managed to learn a ton.