How to check AR15 headspace
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- Опубліковано 15 вер 2024
- Ejector pIn and extractor removed. FOR NEW BUILDS USE A "NO GO" AND "GO GUAGE" TO CHECK FOR AND OVERSIZED OR UNDERSIZED CHAMBER. Use a field gauge on older rifles that will drop a no go. IF YOUR RIFLE CLOSES ON A "FIELD GUAGE" OR WONT CLOSE ON A "GO GUAGE" DO NOT SHOOT IT!!!!
I test mine with a live round and pull the trigger.
1) failure to verify headspace with an actual go-gauge means you may not discover an undercut chamber/bolt combination until that live round explodes in your face.
2) chambering on a no-go is not grounds for rejection at that point. it only tells you that barrel/bolt is nearing the end of its service life.
and THAT'S why you have a field gauge.
A field gauge is not necessarily meaning the barrel is done for. It has about another 1k-2k life left but only if you caught it. The idea is you’ll take it off the field and into the armory for change but if necessary you can still use it in a all out combat situation. Definitely not a good idea to keep using it or buying a barrel that fails a field. For civilian you’ll want to stop using it and immediately change the barrel out.
If it seats it yeets. Don’t be like me ladies and gentlemen.
Exactly the approach I’m talking. Thanks!
If at all possible, do this with the barrel removed from the upper, and use only the bolt. Get a good feel, then reassemble, then do it again. This method lets you get a true feel for if your GO is sloppy or not. But that’s just if you want to split hairs.
Maybe if the title says Go / No Go it would be good to have the Go gauge as well.
You’re not supposed to slam the bolt on the gauge. It’s only necessary to remove the ejector. Like someone else said, take the barrel off and use just the bolt. If you don’t want to take the barrel off you need to remove the gas rings on the bolt so you don’t have to apply much pressure to move bolt forward
This video is dangerous. A GO gauge actually is more important than a NO GO gauge, although you should use both unless you buy a bolt matched to that specific barrel.
A bolt that won’t close on the Go gauge is significantly more dangerous than one that will close on the No Go gauge. If the chamber is too short, a cartridge may get shoved into the chamber but the bolt stops before it’s able to close. Inertia causes the firing pin to hit the primer anyway and you have a “slam fire” or out of battery detonation. This would be *BAD*. 💥 Even if the bolt does manage to slam closed, the bullet might be jammed into, or be very close to, the lands, resulting in excessive chamber pressure. Still a bad thing.
If the chamber is too long by a few thousandths, your brass just stretches more than it should. Not good if you reload, but not an explosion in your face. If the bolt closes on the No Go gauge but not on the Field gauge you’re still OK although you don’t want that to happen on a new build. (Several other comments make this same point.)
Have you ever touched a BCG? The firing pin isn't long enough to reach the cartridge if the bolt hasn't rotated. This is by design.
@@firewavey have you ever heard of a slam fire? Yes, they are even more rare in the AR-15 platform than M1 and M14s but it is possible. Are you saying that the firing pin *never* protrudes more from the bolt face than spec? Or are you saying don’t worry about short headspace because it doesn’t matter?
It is a dangerous video and should be taken down .
Absolutely correct you should have a go gauge for an undersized chamber
You should use the 5.56 military TDP 1.4646 go gauge, not the 223 commercial 1.4636 go gauge being sold by most vendors as a 5.56 go gauge. If the bolt closes on a no go gauge it does not mean the chamber has failed, only if the bolt closes on a field gauge does it mean the chamber is to long and has failed...
Go, no go and field for new or worn
You should also have a field gauge for a gun that’s not new
Yeah I've never worried about it but I use quality parts
What if we just swapped out the upper and installed the same barrel and bolt from the same company that makes the bolt and barrel
I would still use a GO and NO GO GUAGE for a new build I have had a barrel from BCM (11.5" lightweight non BFH) close on a NO GO after only 2-300 rounds with all of my bcm factory BCG's and a Maxim SCW BCG... that's out of spec. That Barrel was replaced with a BCM BFH 11.5" that showed in spec for a new build. You will have to order and wait for the gauges from PTG but its worth it.
Great video👍🏽
The kit i got has a 3rd gauge i cant find info on.
Sappy-Seaman that would probably be the “field gauge” . And it would be an lot longer than the “no-go” gauge. It is usually used by the military to get the most use out of a weapon before repairs are done to it.
the field guage is the longest of the three. should a bolt close and lock with that chambered, it's time for replacement of the barrel or bolt itself due unsafe and excessive headspace.