AR Build/Headspace

[TAZ]

You fire every factory loaded round based on that same faith.


Just sayin....


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LOL.. quite true. There are things I can control and then there are things I can't.

 

[Savage20]

You could control it by loading your own.

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[robertc1024]

I wouldn't worry about it. The only AR round (since OP didn't say which one) I'm aware of that you have to be careful about is the 6.5 Grendel. There are type I and type II that have different depths on the bolt face that have to match the barrel.

 

[Dawico]

Why do y'all feel that way?

In laymans terms, AR bolts lock up directly into the barrel. If the parts are milled correctly then there is no way for the headspace to be off. Short of machining the parts again there is no way to adjust it either. The action (upper) just hold the parts in alignment but doesn't really do anything after lockup.

In most other firearms the action bridges the gap between the barrel and bolt. Screwing the barrel in or out adjusts the headspace. The bolt locks into the action and the barrel is screwed into the action. The action holds the two together.

You can actually lock your bolt into the barrel without them even being in an upper in an AR. Technically you could safely fire it that way too.

This is why it is unusual to check the headspace on an AR.

 

[Davetex]

In laymans terms, AR bolts lock up directly into the barrel. If the parts are milled correctly then there is no way for the headspace to be off. Short of machining the parts again there is no way to adjust it either. The action (upper) just hold the parts in alignment but doesn't really do anything after lockup.

In most other firearms the action bridges the gap between the barrel and bolt. Screwing the barrel in or out adjusts the headspace. The bolt locks into the action and the barrel is screwed into the action. The action holds the two together.

You can actually lock your bolt into the barrel without them even being in an upper in an AR. Technically you could safely fire it that way too.

This is why it is unusual to check the headspace on an AR.

Thanks for that explanation, very informative. I was never quite clear on that and have always checked with a pair go no-go gauges. I probably won't continue to do that now. I have a bolt ejector tool, but it's still a PIA to do it.

 

[Dawico]

Thanks for that explanation, very informative. I was never quite clear on that and have always checked with a pair go no-go gauges. I probably won't continue to do that now. I have a bolt ejector tool, but it's still a PIA to do it.

AR's design are the reason anybody can build one. The most important part (headspace) is already checked and safe. Everything else is just knocking pins in and tightening threaded parts. Easy peasy.

 

[Mike_from_Texas]

In laymans terms, AR bolts lock up directly into the barrel. If the parts are milled correctly then there is no way for the headspace to be off. Short of machining the parts again there is no way to adjust it either. The action (upper) just hold the parts in alignment but doesn't really do anything after lockup.

In most other firearms the action bridges the gap between the barrel and bolt. Screwing the barrel in or out adjusts the headspace. The bolt locks into the action and the barrel is screwed into the action. The action holds the two together.

You can actually lock your bolt into the barrel without them even being in an upper in an AR. Technically you could safely fire it that way too.

This is why it is unusual to check the headspace on an AR.

Very good explanation.


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[TX14239]

In laymans terms, AR bolts lock up directly into the barrel. If the parts are milled correctly then there is no way for the headspace to be off. Short of machining the parts again there is no way to adjust it either. The action (upper) just hold the parts in alignment but doesn't really do anything after lockup.

In most other firearms the action bridges the gap between the barrel and bolt. Screwing the barrel in or out adjusts the headspace. The bolt locks into the action and the barrel is screwed into the action. The action holds the two together.

You can actually lock your bolt into the barrel without them even being in an upper in an AR. Technically you could safely fire it that way too.

This is why it is unusual to check the headspace on an AR.

Spot on. +1