AR10 headspace

[Cs68]

A guy at my local range is selling an 18" krieger barrel that's exactly what I'm looking for to build around, it comes with a headspaced bolt. Do I need to run go/no go gauges if the bolt was headspaced when the barrel was made for him?
I'm leaning towards buying gauges to check, but wonder if it's necessary because the bolt is going in a different carrier?
Thanks for any info

 

[whatsupdoc]

Not necessary headspace is preset.

 

[TonyAngel]

If you’re purely trying to establish the accuracy of the cartridge maybe. But if you want to establish the accuracy of your rifle system, you need to introduce heat to the barrel and barrel extension. This is what running it in a comp or fight is going to do. The round getting pre heated inside the barrel extension is going to change the velocity. The barrel heating up is going to cause POI shift. Are we using these things for bench shooting or to fight/compete with?

Not necessary headspace is preset.

Although that is the idea, getting a barrel and bolt from a "guy at the range" could be iffy. If you really know the guy and the guy that he had do the headspace, odds are it won't be a problem.

Of course, having at least a no go gauge on hand is never a bad idea, as is checking headspace.

 

[yosemite_sam]

If you’re going to build an AR you need headspace gauges. Go and no go. I have had multiple new barrels/bolts fail no go and fail go. I had a Noveske that failed to chamber GO with its “headspace bolt”. Chamber was retardedly tight. Great way to spike pressures.

If you have to ask whether or not the bolt being in a different carrier affects headspace you need to understand more about this weapon before you build your own. And cause I’m not a dick, the bolt doesn’t care which carrier it is in.

You should buy a set of headspace gauges, a bolt vise, and some roll pin punches. Break down the bolt and check the headspace with your buddy before you buy the barrel.

 

[Cs68]

If you have to ask whether or not the bolt being in a different carrier affects headspace you need to understand more about this weapon before you build your own. And cause I’m not a dick, the bolt doesn’t care which carrier it is in.

That's why I asked, seems like if you look online you get 2 schools of thought, it's absolutely going to change things, or no it won't make a difference. Lots of anecdotal stories of "my brand x custom barrel shot super tight with the supplied bolt in multiple different carriers" or "I switched to another bcg/bolt altogether and the groups didn't change."

 

[Cs68]

Although that is the idea, getting a barrel and bolt from a "guy at the range" could be iffy. If you really know the guy and the guy that he had do the headspace, odds are it won't be a problem.

Of course, having at least a no go gauge on hand is never a bad idea, as is checking headspace.

Barrel and bolt were done by precision firearms, so it's not like I'm buying a questionable barrel off the back of a U-haul truck.
Having the gauges to check was my plan for the get go, built a handful of rifles, but first time replacing a barrel.

 

[yosemite_sam]

That's why I asked, seems like if you look online you get 2 schools of thought, it's absolutely going to change things, or no it won't make a difference. Lots of anecdotal stories of "my brand x custom barrel shot super tight with the supplied bolt in multiple different carriers" or "I switched to another bcg/bolt altogether and the groups didn't change."

Checking headspace isn’t about accuracy, although some folks feel that a tighter chamber yields more accuracy. Checking headspace is about knowing that your firearm is safe to operate. A chamber that is too tight or too baggy can cause over pressure/case ruptures.

Checking minimum is just as important as maximum. A chamber that is too tight will still chamber a round as brass deforms easily.

 

[Cs68]

Checking headspace isn’t about accuracy, although some folks feel that a tighter chamber yields more accuracy. Checking headspace is about knowing that your firearm is safe to operate. A chamber that is too tight or too baggy can cause over pressure/case ruptures.

Checking minimum is just as important as maximum. A chamber that is too tight will still chamber a round as brass deforms easily.

I understand it's about pressure, I was using the accuracy claims as an example as to why I'm wondering if it's totally necessary for an AR platform. Most people just plug and play whatever bolts or carriers in their rifles, I've never really heard of issues when doing so. I understand the issues that can be had, but wonder if commercial vs a custom barrel chambering would be enough to warrant the precaution? I'll most likely check anyway just to be safe tbh.

 

[Jscb1b]

I would check it just to be safe.

 

[yosemite_sam]

I understand it's about pressure, I was using the accuracy claims as an example as to why I'm wondering if it's totally necessary for an AR platform. Most people just plug and play whatever bolts or carriers in their rifles, I've never really heard of issues when doing so. I understand the issues that can be had, but wonder if commercial vs a custom barrel chambering would be enough to warrant the precaution? I'll most likely check anyway just to be safe tbh.

You won’t regret having a set of go/no go gauges. I’ve used mine many times to gauge mine and friends barrels/bolts. Also don’t try to break down your bolt for head spacing without the bolt vise. Very very well worth the $35.