savagetroll
Inactive
I am in the process of building my first AR15. Going with a Daniel Defense CHF barrel and Daniel Defense bolt. My question is, is it necessary to check headspace, and if so what is the best way to do so? thanks for any input
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First AR build/headspace
- Thread starter savagetroll
- Start date
I've built three ARs and never checked the headspace but it's not a bad idea. If you want to check, get a no-go and field headspace gauge.
http://www.brownells.com/.aspx/lid=12555/GunTechdetail/Headspace-Gauges-And-How-To-Use-Them-Part-I
http://www.brownells.com/.aspx/lid=12555/GunTechdetail/Headspace-Gauges-And-How-To-Use-Them-Part-I
FrankenMauser
New member
Check headspace before installing the barrel.
Strip the bolt.
Clean the gauge, bolt, barrel, barrel extension, and locking lugs.
Insert the gauge, and see if the bolt will lock. (Free-spinning in the barrel extension is fine when using a "go" gauge.)
I've built half a dozen, or more.
Most had no issues with headspace (and weren't checked with actual gauges - at least initially).
But the one that did have bad headspace... I could have saved myself innumerable headaches by checking headspace before installing the barrel, rather than after running into chambering issues.
Strip the bolt.
Clean the gauge, bolt, barrel, barrel extension, and locking lugs.
Insert the gauge, and see if the bolt will lock. (Free-spinning in the barrel extension is fine when using a "go" gauge.)
I've built half a dozen, or more.
Most had no issues with headspace (and weren't checked with actual gauges - at least initially).
But the one that did have bad headspace... I could have saved myself innumerable headaches by checking headspace before installing the barrel, rather than after running into chambering issues.
The only AR headspace problem I've found was on a 5.45x39. I think the barrel/extension had been headspaced with a 7,62x39 bolt or something stranger yet?? First round separated the steel case leaving the shoulder and neck in the chamber.
I have found a couple of .223/5.56 chambers that were too tight with certain bolts requiring a little trial and error fitting with different bolts. I don't swap bolts after more than a few test rounds unless there's a specific problem. The way I see it: new bolt-new chamber= no problem, new bolt-relatively low round chamber=likely no problem, high round used bolt-any chamber other than the one it came from=expect a problem.
I have found a couple of .223/5.56 chambers that were too tight with certain bolts requiring a little trial and error fitting with different bolts. I don't swap bolts after more than a few test rounds unless there's a specific problem. The way I see it: new bolt-new chamber= no problem, new bolt-relatively low round chamber=likely no problem, high round used bolt-any chamber other than the one it came from=expect a problem.
savagetroll
Inactive
Thanks for all of the advice. New quality barrel and bcg, but never hurts to be sure.
You really shouldn't need to as long as the barrel was chambered correctly and the extension is in spec..and with both barrel and bolt by Daniel Defense it's VERY unlikely you're going to find an issue. No more likely, IMO, than an 700 rolling off the line at Remington with excessive headspace.
You could always take an inert round, or case, confirm the bolt rotates fully into battery easily, and use a couple layers of cellophane packing tape (if you have a mike to measure the thickness of it) added to the case head to approximate a no-go gauge.
If you buy a gauge, no-go is what you want...no need for a field gauge. If it closes on a no-go you need take it no further on a new rifle.
It would be interesting to know if D.D. actually verifies headspace on assembled uppers or rifles as part of QC, or if they just assemble the components.
You could always take an inert round, or case, confirm the bolt rotates fully into battery easily, and use a couple layers of cellophane packing tape (if you have a mike to measure the thickness of it) added to the case head to approximate a no-go gauge.
If you buy a gauge, no-go is what you want...no need for a field gauge. If it closes on a no-go you need take it no further on a new rifle.
It would be interesting to know if D.D. actually verifies headspace on assembled uppers or rifles as part of QC, or if they just assemble the components.
When talking about headspace on an AR type rifle is like asking the proverbial question: What came first, the chicken or the egg. You will find 1000 people that say headspace is not necessary, and you will find 1000 that say it is necessary. As mentioned above if you do decide, using a GO, NOGO gauge will suffice. If you decide not to headspace, that too will be find.
Theoretically, the chamber was cut to dimension using a "bench bolt" which to me indicates a test bolt gauged to be within specifications for the design. I don't know the tolerances allowed for bolts or barrel extensions but there's always a possibility of ending up with marginally long or short headspace due to tolerance stacking.
I keep a handful of inert cartridges for testing function of new AR assemblies. I also have a "test only" firing pin(tip ground off to prevent ANY chance of AD) that I can use with live ammo for function testing. I often use this to check fit of reloads on one of my tight chambered AR's to make sure they fully chamber.
I keep a handful of inert cartridges for testing function of new AR assemblies. I also have a "test only" firing pin(tip ground off to prevent ANY chance of AD) that I can use with live ammo for function testing. I often use this to check fit of reloads on one of my tight chambered AR's to make sure they fully chamber.