Headspace question

[chavezz556]

I'm building a new upper in 224v.. I bought a 20" Larue barrel with matching bolt.. my question is do I need to headspace it?

I will call Larue tomorrow to make sure, but I'm getting antsy and wanted to put it together tonight!

Also should I be fine using a standard BCG from my AR?

Thanks,

 

[Precision Underground]

If the bolt came with the barrel from larue it should already be headspaced.

 

[Precision Underground]

Yes your carrier should work fine.

 

[chavezz556]

Yes your carrier should work fine.

Appreciate it...

Thanks,

 

[MontanaMan]

If the bolt came with the barrel from larue it should already be headspaced.

This ^^^^^ that's the whole purpose of buying a bolt with a barrel.

MM

 

[308pirate]

I'm building a new upper in 224v.. I bought a 20" Larue barrel with matching bolt.. my question is do I need to headspace it?

Don't you think it's premature to be building your own rifle when you don't know this?

 

[Precision Underground]

Don't you think it's premature to be building your own rifle when you don't know this?

Ehhh. I had to learn on my first ar and I turned it onto a .5 MOA gun. Though I am a master jack-leg tinkerer.

 

[308pirate]

Ehhh. I had to learn on my first ar and I turned it onto a .5 MOA gun. Though I am a master jack-leg tinkerer.

I'm not saying he shouldn't build one until he's a master gunsmith. Just to learn the basics before jumping in......

 

[Precision Underground]

I'm not saying he shouldn't build one until he's a master gunsmith. Just to learn the basics before jumping in......

Hey, better to be too careful than not with headspace! That's more of an industry thing to know anyway. If you read a book or watched a video on building an ar they all would say "make sure your bolt is headspaced to the barrel". He just didn't know that when a company sends a bolt with a barrel it has already been headspaced.

 

[Bandit31]

when a company sends a bolt with a barrel it has already been headspaced.

Generally speaking, that's correct but sometimes stuff falls through the cracks. I've ordered three barrels with "matched bolts" that didn't headspace from well known manufacturers. One even came with a bolt so out of spec it wouldn't even go into battery.

I'd buy the gauges, you may need them or you may not but it's cheap insurance IMO, and with the valk gaining steam, i'm sure someone else wouldn't mind taking them off your hands when you're done with it.

 

[MontanaMan]

I'd buy the gauges, you may need them or you may not but it's cheap insurance IMO, and with the valk gaining steam, i'm sure someone else wouldn't mind taking them off your hands when you're done with it.

This is true..............best to always have your own gauges if you're going to be doing a few now & then.

MM

 

[longshot2000]

I've ordered three barrels with "matched bolts" that didn't headspace from well known manufacturers. One even came with a bolt so out of spec it wouldn't even go into battery.

.

I am sure that is true, but isn't a moot point? I mean, if you find your bolt / barrel fails the headspace test, not much you can do about it, with the barrel extension in-place and gas port drilled. You are left with tossing the barrel or the bolt, and then you are not sure which one.

 

[chavezz556]

Don't you think it's premature to be building your own rifle when you don't know this?

I've learned how to fly fish, make knives, reload, work on my cars from forums.. it's always nice to be able to have people help out you know..

One even better is to come up with an extra cunty comment.. one that you can tell your friends about at the bar. I'm dead serious about this. Could possibly be one of the best things about the internet...

Anyway I called Larue today and they said I'm good to go, but I still had a friend double check it..

Thanks,

 

[Bandit31]

I am sure that is true, but isn't a moot point? I mean, if you find your bolt / barrel fails the headspace test, not much you can do about it, with the barrel extension in-place and gas port drilled. You are left with tossing the barrel or the bolt, and then you are not sure which one.

If a customer orders a barrel with a matched bolt and it doesn't headspace, it's on the manufacturer to diagnose and find a solution to the problem whether it's just by replacing the bolt or both the barrel and bolt. The only loss on the customers end is the time they have to take out of their life to contact said manufacturer and get the problem, that shouldn't have been an issue to begin with, squared away.

 

[Rocketvapor]

With the difference between two bolt dimensions determining headspace from that end, what would a barrel maker do if you did NOT buy the Matched Bolt? What dimensions would he use?
Just rounding to the nearest 0.001" I get ,282" lug length, and a .127 bolt face depth, for a head space of .155 on the bolt side.
(just measured another)
What do you guys get for "bad bolts"?
EDIT: 3 of my 5.56 bolts. I get .282 -.126=.156, .281 -.126=.155, .282 -.126=.156.
A LWRC 6.8 bolt .279 - .123 = .156.
and another 6.8 bolt .280 - .125 = .155
0-1 micrometer and 6 Dial Caliper zeroed for depth on a flat. Errors will be mostly with the depth measurement.
Corrected keyboard errors.

 

[padom]

I am sure that is true, but isn't a moot point? I mean, if you find your bolt / barrel fails the headspace test, not much you can do about it, with the barrel extension in-place and gas port drilled. You are left with tossing the barrel or the bolt, and then you are not sure which one.

Actually no your left with returning the said barrel/bolt to the place of purchase or manufacturer and they send you a new one.

 

[Nukes]

This ^^^^^ that's the whole purpose of buying a bolt with a barrel.

MM

…from a reputable source.

 

[Blutroop]

Don't you think it's premature to be building your own rifle when you don't know this?

How else is he supposed to learn?

 

[308pirate]

How else is he supposed to learn?

Check....mate

 

[Rocketvapor]

You buy a matched barrel/bolt from a reputable company and check headspace at home and find it is out of spec.
Odds are you will be out postage both ways