Can anyone school me on AR Headspace Gages?

[mugsy]

Point me to a good primer?
Where to buy a three gage set?
Is a three gage set needed or only a field reject and no go?

I am confused.

 

[CAR-AR-M16]

See if this helps:

http://www.brownells.com/.aspx/lid=11624/learn/

 

[mugsy]

Thanks and PM sent to you, Bull and Sanford ref same subject.

 

[tRidiot]

I asked about this some time back... not because I thought it was a NECESSITY, but because it was something extra to learn about and an extra step to ensure safety and functionality.


I wouldn't recommend asking here. lol

 

[SPDguns]

I asked about this some time back... not because I thought it was a NECESSITY, but because it was something extra to learn about and an extra step to ensure safety and functionality.


I wouldn't recommend asking here. lol

C'mon, man! This is the internet, so it must be true!!!!!! LOL

 

[mouthpiece]

https://www.okshooters.com/showthread.php?187490-How-many-AR-s-have-you-built-AND-headspaced

Seriously, Let me know if you find one out of spec.

 

[TonyRumore]

When a manufacturer is setting the head space on a gun, they will use a Go and No-Go gauge. They don't use a field gauge. The difference between the Go and No-go is usually around .005" or so. Some cartridges can have a larger range up to around .010", but personally that's just really sloppy if you ask me. If they set the head space at zero, the bolt will be dragging on the Go gauge. They can also set it out at .001, .002, .003" etc off the go gauge, until they run out to the No-Go limit. Sloppy gunsmiths will just get it "somewhere" between the two gauges and call it good. That is garbage work if you ask me. If you have your act together you can set the head space plus or minus .0005". At Tromix, we make our own gauges so we can tighten the tolerance between the Go and No-Go to a .0015" spread. Depending on the caliber/situation, it might be closer to the Go gauge, or out closer to the No-Go.

For example, on the .458 SOCOM barrels, we run the head space at the long end of the limit since Starline has a very hard time holding the shoulder position consistent. So, many times new brass won't chamber if you're not out toward the No-Go limit. However, on the .450 Bushmaster barrels, both Hornady and Remington trim the brass way too short, so if you don't chamber it up close to the Go gauge, you're going to get light primer strikes.

So what does that mean to you? Well, even with gauges, you have no idea exactly where the head space is set, other than it's somewhere between the two gauge limits. However, if you are past the No-Go limit, that doesn't mean it is unsafe to shoot. That's where the Field gauge comes in. The Field gauge is the "safety" limit for lack of a better term, and will be out past the No-Go limit. If the bolt closes on the Field gauge, the head space is usually considered to be beyond shootable limits.

Tony Rumore
Tromix

 

[mightymouse]

Thanks, Tony. Excellent explaination.

 

[uncle money bags]

Nicely done, Tony.

 

[dennishoddy]

When a manufacturer is setting the head space on a gun, they will use a Go and No-Go gauge. They don't use a field gauge. The difference between the Go and No-go is usually around .005" or so. Some cartridges can have a larger range up to around .010", but personally that's just really sloppy if you ask me. If they set the head space at zero, the bolt will be dragging on the Go gauge. They can also set it out at .001, .002, .003" etc off the go gauge, until they run out to the No-Go limit. Sloppy gunsmiths will just get it "somewhere" between the two gauges and call it good. That is garbage work if you ask me. If you have your act together you can set the head space plus or minus .0005". At Tromix, we make our own gauges so we can tighten the tolerance between the Go and No-Go to a .0015" spread. Depending on the caliber/situation, it might be closer to the Go gauge, or out closer to the No-Go.

For example, on the .458 SOCOM barrels, we run the head space at the long end of the limit since Starline has a very hard time holding the shoulder position consistent. So, many times new brass won't chamber if you're not out toward the No-Go limit. However, on the .450 Bushmaster barrels, both Hornady and Remington trim the brass way too short, so if you don't chamber it up close to the Go gauge, you're going to get light primer strikes.

So what does that mean to you? Well, even with gauges, you have no idea exactly where the head space is set, other than it's somewhere between the two gauge limits. However, if you are past the No-Go limit, that doesn't mean it is unsafe to shoot. That's where the Field gauge comes in. The Field gauge is the "safety" limit for lack of a better term, and will be out past the No-Go limit. If the bolt closes on the Field gauge, the head space is usually considered to be beyond shootable limits.

Tony Rumore
Tromix

perfect explanation. Thanks!