Head space ?

[Bullets&Whitewalls]

I assembled my LR .308 upper recently and put it aside until I was able to get headspace gauges. Today they showed up and I found that I can close the bolt on both the go and the no go gauge. The no go is slightly harder to close but it does still close. The way I did it I left the bolt assembly completely together. I am going to try it with the bolt only without the extractor on it to see what I come up with. It seems like that would be a better way to do it. Any advice would be appreciated , kinda worried that it closed on the no go. Should I get a field ? And can someone tell me the difference as I'm having a hard time figuring that out even searching here and you tube. My Google fu is weak today. Thanks for your time guys. I did find some good info finally on the brownells site and another cmp site. I need to get the Field gauge and see what happens there. It looks like my head space just might be a tad bit on the larger side. If it closes on the field then I'm in trouble. But I'm still unsure if I like the idea of it being on the larger size. What do you guys think

[Bullets&Whitewalls]

I meant ejector

[Bullets&Whitewalls]

I disassembled the bolt and checked they both go in way too easy.

[Bullets&Whitewalls]

Here's the pic with the no go locked in. Too easy no Bueno.

[ar15barrels]

The standard procedure when a bolt and barrel fail headspace is to first replace the bolt, test again and if it still fails, then replace the barrel.

Do you know if your barrel is made to 308 hedspace specs of 7.62x51 headspace specs?
The two specs are not the same.
Do you know what spec your headspace gauges are meant for?

A 7.62x51 spec barrel could accept a 308 no-go gauge and be completely within 7.62x51 specs.

[Bullets&Whitewalls]

That is awesome Info Randall thank you. My barrel is a rainier chambered in .308 and my Clymer gauges are for .308 as well. I did wonder though about the different chambers.

[ar15barrels]

That is awesome Info Randall thank you. My barrel is a rainier chambered in .308 and my Clymer gauges are for .308 as well. I did wonder though about the different chambers.

A 308 chamber reamer CAN be used to chamber either 308 spec length OR 7.62x51 length spec.
The difference is 0.002" of length across the board:

308
go 1.630
no-go 1.634
field 1.638

7.62x51
go 1.632
no-go 1.636
field 1.640

So now you see the dimensions, you can see how a gun that was at 1.632" to 1.636" would fit both 1.630" and 1.634" gauges.

If you were to get a 1.638" gauge, a NEW 7.62x51 spec barrel should not accept it.

"Go" and "No-Go" gauges are for new guns.
"Field" gages check used guns.
A used gun can acceptably fail a "no-go" test and still be considered safe.
A used gun is considered unsafe when it fails a "field" gauge test.

[Bullets&Whitewalls]

Are you saying that even a .308 barrel could be sized for 7.62 51 specs even though it only says the chambering is .308? I just want to make sure I understood your reply. It makes sense to me since I have heard of people using the 7.62 round with these barrels.

[Bullets&Whitewalls]

My stuff is brand new. Rainier barrel but I'm not sure who made the bolt. I got it from a friend of mine. It "appears" to be of good quality and is nickel boron coated. I know that doesn't mean squat. The no go gauge does hesitate slightly more when I push it in, but it does go all the way. I am just using one finger slight pressure.

[ar15barrels]

IF the barrel is claimed to be 308 spec, it SHOULD pass both 308 go and no-go tests when new.
A barrel/bolt that fails either of the 308 go and no-go tests would NOT be a PROPER 308 dimensioned barrel.

That's not to say that it would not be safe to shoot 308.
It's probably just fine, but it's not in-spec.
Try a field gauge.
If it fails that, kick it back to Ranier.

[Bullets&Whitewalls]

I will do just that. Thank you so much for the replies.

[Bullets&Whitewalls]

The field gauge showed up and does not close! I've talked with ages others that have similar set ups and had the exact same thing happen. Their ries are shooting fine and showing no case damage to fired rounds. Saturday morning he we come.