I called Dave Manson at Manson Reamers to ask about his head space gages and got schooled, including misinformation when it comes to gages in general and on this forum in particular.

1. The cutout on the back of his gages will not provide clearance for the ejector and was never intended to. It is there to drive the gage during manufacture when grinding between centers.

2. The ejector and extractor do not have to be removed when checking head space on an AR and will not affect the results. The tension on the extractor will have to be overcome but after that the bolt will either close or it won't.

3. The .223 gage is only .002 shorter than the 5.56 gage. If you have both calibers of rifles you can get the .223 gages and use them in your 5.56's and be close enough if you are just checking and not building/reaming barrels.

4. If you are on a budget just get the Go and Field gages. If the bolt wont close on the Field gage the rifle is still safe to shoot. A NO GO is basically for gunsmiths reaming a new chamber.

Hope this helps if you are getting ready to purchase gages.

Why would a .223 and a 5.56 have different headspace gauges? The cartridge is the same. The difference between 5.56 NATO and .233 Remington is in the throat of the chamber, which is closer to the muzzle than the point at which headspace is measured. I'm pretty sure 1.4736 is the max regardless of whether the gauge says 5.56 or .223. Does .223 have a different minimum spec?

Don't know and I didn't ask but all 3 manufacturers I checked sell .223 and 5.56 gages with different part numbers.
.308 and 7.62 seems to be the same way.

While I appreciate your post, some information you may be interested in.  

 
1. I have reported in many threads all my Manson gauges have a slice in the rear that keep you from having to remove the ejector.  I have no idea why the slice was put there, so I appreciate the explanation, but that slice works superbly on my 5.56 and 6.8 gauges to house the ejector.  So regardless of the reason its there, it works for me on the stated use.  YMMV.



2. Consult the manual.  Yes I have been able to "check" headspace with the ejector in on other gauges without a slice.  You should remove them to obtain a correct reading.  Will it work without removing them, yes til things get tight, and things already start out real tight.  I am OCD like that.  



3. When I called and Emailed Manson, PTG, and another gauge manufacturer, I was told the gauges were exactly the same only named differently and I did not need to buy two sets of gauges.  YMMV this is only what I was told by multiple sources.  



4. The Field gauge is used to pull a worn barrel out of service.  If you feel comfortable with your brand new barrel being spec'd to worn out tolerances feel free to go that route.



No doubt Dave Manson is a smarter man than myself on this stuff.  But your reasoning in your explanation requires further information for people to make their own decisions.  So thanks for the post, but it doesn't end there with your points.  There is just a little more to the story.  But thank you for the information you did post.
 


EDIT to 3.  I no longer have the email due to whatever reason, I was actually sent blue prints of the .223 and 5.56 gauges from PTG and maybe Manson I cannot remember for sure, which showed, while different calibers were written on the gauges, the gauge was built to the same specs.  Again, for the sake of information, YMMV.  Forster was the only company with different specs.

Here is a Chart that shows the difference between the two calibers and gages.
The 5.56 is .003 to .0036 longer than the .223 on some of the gages.

http://www.ar15barrels.com/data/headspace.pdf

Not to be the contrarian, but I have posted this here before...(and I was "corrected" by the usual forum "experts" then, and so I expect to be "schooled" once again, but so be it....)
According to the fine folks at BCM, and posted on TOS (which I can link to, but I'm not sure that is allowed here), but this is a direct copy and paste:

And that info is solid. Since we can't really change nor adjust the headspace on our AR's, all we really need is the Field Gauge, which tells us whether or not our headspace is acceptable.
It doesn't tell us our barrels are worn out, it simply assures us that the headspace is within acceptable measures or it isn't.
If it passes the Field Gauge Test, it's safe to use. And that's really what we need to know.

There is more to it than that.  This has been explained in numerous head space threads.  Cool that you got information memorized from Internet forums.  I only know what I was taught in armorers school.  You could have a barrel that is "brand new" yet have 80% of spec and still pass the field gauge which would make it "safe" but a terrible value.  Guess we can agree to disagree.  

 


You can ream a stainless barrel.  You can pair up another bolt.  Or you can send back out of spec equipment.  Good luck with your philosophy.
 

+1 for Lug1

The point to checking No-go is to be able to reject an out of spec new barrel.
A barrel that fails the US mil-spec No-go gage may be safe, but have a short service life.
Each to his own, but when I buy a barrel I also expect a long service life.
It is also my take that loose headspace is not an enhancement to accuracy.

For a given measurement the gage is the same for 223 REM or 5.56mm NATO chambers.
The difference is the specifications for Go, No-go, and Field.
The SAAMI specs have changed since that chart that is always brought up was made.
The mil-spec falls within the SAAMI min/max range.
Mil-spec for headspace is different to enhance reliability in hard use under adverse conditions.
SAAMI’s specs are to make sure a max tolerance cartridge will fit/be safe in a min tolerance chamber and vice versa.

There is even more of a disconnect between 308 WIN and 7.62mm NATO.
That is a discussion to itself.

Thanks for being so "snippy. It really makes your response sound much more adult.
I haven't "memorized" anything from any internet forums, and it's not my "philosophy", it came directly from the (apparently uneducated, since they obviously didn't attend armorers school) folks at BCM.
So, I was simply sharing information posted by one of the most highly respected suppliers in the industry.
Maybe you should call them and share your experience with them, since they're the ones misleading the forum members with their errant "philosophy".
Once again, I apologize for trying to share what is accepted elsewhere as useful knowledge.

That IMO is a somewhat of a self-serving “philosophy” for a vendor.
Especially since there are fairly regular posts reporting bad headspace.
Also I take my weapons to the “field”, but I am the builder and all maintenance levels for them also.
BCM may have had relatively few problems compared to some, but I never the less check the parts I get from them the same as I do parts from other sources.

My .02 in talking to barrel manufacturers & diving into wildcat R&D...

I was told by many that a "Field gage" was a waste. One even said, and I quote, "I have purchased three gage sets & never, not once, have I used a Field gage." That was from a US National Long range Champion & one of the best barrel makers in the country. He then told me, "Go, No-Go, the rest is BS & a waste of money"

Barrel makers make the barrels, they understand every aspect of that chamber they are making, if they are worth their salt. Chambers in barrels wear with shooting, a No Go tells you when it has worn too much. How many of you guys check headspace after initial assembly & many thousand rounds? A knowledgeable reloader will. He will even check fired cases in a case gage to see how the chamber is wearing over time.

In adition, what I have seen in comparison of 223 Rem, 556 NATO & 223 Wylde, the headspaces spec is identical, according to chamber prints. Throat & lead is a different story...

Now, that being said, the 223 Wylde has a much larger chamber shoulder diameter than the other two. That means the expansion when being fired alter the other aspects of the case stretch. In other words the energy in the round expands the shoulder, not the neck so as to limit neck stretch.

I incorporated this aspect into my 35KLR cat just to see how it worked under high pressure situations. Brass life may well be reduced, by a small margin, depending on brass composition, but the chance of a "Jam" due to the neck stretching is greatly reduced along with an acuracy advantage incase a case is made a tad long over what I specify.

For all you guys out their that don"t reload and have never used a case gage, you can not begin to understand this relationship. A manufactured case falls withing a certain guideline of headspace, Each chamber is different, one chamber will have different hedspace depending on when in the reamer cycle it was made. Manufactrurers of ammuniton have to produce ammunition in the happy medium of this specification so as to make the safest "Average" of pressures that may be encountered by the end user.

Again, just my .02...

Well I learned one thing from this thread, discussing headspace gages is like discussing politics.
No one will ever agree and facts like beauty are in the eye of the beholder.

When I started my conversation with Dave Manson he thought I was a gunsmith or someone making a barrel.
He suggested getting Go and No Go gages.

When I explained I was an end user wanting to check my various barrels when swapping/ trying different bolts he
immediately switched to get a Field gage and perhaps a Go gage.
He could have sold me all 3 gages but was trying to save me $ on something I wouldn't need.

I think we are somewhat confusing the needs of different jobs. I should have been more specific in the title of my post.

Maybe an "end user" is closer to "Field" type use (pardon the pun) than a gunsmith or barrel maker.

My 223 REM match gage set checks all three chambers because the datum line is the same.
I don’t know what the specs are for 223 WYLDE, but US mil-spec is different than SAAMI for Go and No-go.
It makes perfect sense for a match shooter to use SAAMI No-go for his weapon.
However there are a lot of people who will shoot an AR until the groups get too big, the weapon fails the max chamber gage, or in some cases until they start getting blown primers and case splits.
The specs for the headspace measurements are subject to change as anyone with the older 223 REM gages and a set of the newer gages knows by example.

I have one barrel with a .223 chamber, a Harris SS 19" bull match. When ASA tested it before shipping they used IMI 62gr M885.
I really don't want to shoot 5.56 in it but it sure didn't bother them. Anyone else find that strange?

Anyway all of my other barrels (7) are 5.56. Manson suggested getting .223 gages and use them for everything.
Or I could go 5.56 and use them for everything. Suggestions?

I don't really want to buy both sets for one .223 barrel.

You do realize that the solution to your conundrum is in your statement of a non-question.

You are correct I was snippy.  That wasn't the spirit it was written in, but as I retread it, I see my error.  My apologies for being a jerk.  It was not my intention.  


 

BCM still handed out incomplete advice at best.

Thanks for stepping up....but I suppose I was a bit quick on the keyboard as well. No real offense taken, and thanks for getting both of us realigned.
I guess the point BCM was making, and what I was thinking when I pasted their quote, is this: Very, very few of us have any way to correct the headspace on AR's.
We can't adjust it nor change it in any way (other than trying to swap bolts until we magically find a match). All we can do is check it to confirm that our particular rifle is safe to use. And that's what the Field gauge is for.
I have GO and No-Go gauges for My Savage bolt actions, because I can and must set the headspace when changing barrels. But with my AR's all I can do is verify they're safe.
If someone does indeed have the necessary tools and training to effectively adjust-correct-change headspace on their AR's, then yeah all the other gauges are needed.
But for the rest of us, and I'd bet that's probably 95% of AR owners, the Field Gauge is all we need.
That was BCM's point, and one I tried to share.

I am glad you guys made up.

I understand the concept for a Field gage. It can be a good thing to know. Albeit by the time it is to the point in showing the headspace tolerance is too far out of spec you already have a potential disaster on your hands.

Proper use of a No-Go will give you a "Safe" refference that does not exceed the maximum headspace dimension. Once you reach the point where a No Go closes, you have reached the "recomended" headpsace limit & replacement is inevitable sooner than if it doesn't close. As for myself, any barrel that closes on a No Go that is new would be immediately returned.

My point is do not wait until a Field gage closes. You can all do what you want, but never say I recommended it.

Is this the website?  http://www.mansonreamers.com/



I need a set of head space gauges myself.





When checking head space on a .223 Wylde chamber, do you just use the .223 rem gauges or do you have to have a set of .223 Wylde specific gauges? Thanks in advance.

Most any 223 REM chamber should handle a few M855 test rounds with no problem.
Chamber pressures can vary widely between weapons.
My 223 REM match gage set shows 1.4636” as Go, 1.4666” as No-go, and 1.4696” as Field.
I think these are good specs for either for civilian use, although at some point you may also need the Colt spec max chamber gage which is 1.4736”.

For headspace either will work.

http://www.forsterproducts.com/store.asp?pid=24834

Can you explain "that check not just head space".



 

I edited my post sorry. I remembered a post a while back to some Gages that also checked freebore leade. Those are listed under their NATO Gages. Not Wylde. I didn't see any mention about freebore in their gage descriptions now.

My apologies.

Here's an older thread I remember seeing. it answers your question.

Awesome, thank you.



http://www.midwayusa.com/product/366434/ptg-headspace-no-go-gage-223-wylde