Undersized No-Go gauge?

[Eddie Harren]

"Or you could learn to use the no go-go gage for both measurements. Or you could modify the go-gage and turn it into a go to infinity gage." f. guffey

Please translate and when you're done, send the "datums" that I ordered.

 

[Tommie]

I've set-back and rechambered several barrels to Ackley Improved. Have yet to find a need for a No Go gauge. Of course that's assuming to Go gauge is built correctly.

 

[ireload2]

Sorry I missed your question about the .308 case. Your use of already formed brass in either .250 Sav. or .22-250 may prevent you from seeing the full size of a case formed by your FL sizing die.
Trim a .243 or .308 case then size it 3 or 4 times slowly so that the brass has plenty of time to creep and become an exact fit in the FL die. Save this case as a reference. It provides you head to shoulder length of the die. It will also give you shoulder and pressure ring diameters.
Then trim another .243 case and carefully size it until it is a perfect fit in your chamber.
Save this case. Use it to compare to the correct length gunsmith head space gauges. It will tell you your actual chamber length if you zero your Hornady Gage on the headspace. You will also be able to compare your die and chamber.

Thank you all for the informative responses.
Ireload2 & XBBR shooter: Thanks for clarifying the measurements up. I need to quit assuming some things. As I read you, in order for the Hornady comparators to get me close, they have to have a sharp face-to-bore edge that is true to the .347 sized bore. Only then can they be properly zero'd out.
Fguffy: I always look for your hidden gems.
Freestyle: Thanks for acknowledging that I'm not crazy. lol.
SWD: that's what I was thinking- don't overthink and just use the brass as-is in a 'custom' chamber until that gets "improved".

1. The gauges are indeed Pacific Tool....
2. Indeed I am using the "comparators" and should have realized that they cannot be relied on for exact measurements, although this one has a rather sharp face. My others are chamfered.
3. My mistake, I used a once-fired 22-250 to compare to the 250 Sav. The virgin Nosler 22-250 brass measures 0.010 shorter than the virgin Jamison 250 Sav. brass at the same point using the comparator.
4. I just read PTG's description of the Ackley chamber Go and NO-GO setup on their website. He used the original chamber "GO" gauge as the new "NO-GO" to shorten the chamber 0.004 (same neck angle as the old). The new Ackley "GO" gauge is another 0.004 shorter to ensure that the new datum line crushes on the neck juncture of standard cartridges for fire-forming into the "improved".
What this tells me:
5. The standard "GO" is equal to the Ackley "NO-GO" except for diameter.
6. My standard 250 "NO-GO" gauge is equal to my 250 Ack. imp., "NO-GO". They should not be equal. One must be wrong since they cannot both measure the the same.
7. What I should have ordered were standard "GO" and "NO-GO" and an Ackley "GO". That would have provided me with all 4 gauge measurements. It looks like what I have is a functionally standard "GO" and Ackley "NO-GO".
Having spelled out what is what, has helped me immensely. Thank you all for pitching in.

Question to Ireload2: Sizing the .308 Win. to check for size with 250 Savage? I may be missing something else important here but, how/why would I shrink a 0.055 longer/wider cartridge to do the checks with? Wouldn't I need an arbor press: something to get some real crushing power? And wouldn't the shoulders buckle in my RCBS 250 Sav. FL die? How much larger brass can I shorten to make 250 Sav.?
To all:
I accept that since this is functionally a "wild cat" and I can either up-size 22-250 brass and fire-form it, or use re-sized 6.5mm Creedmore once the chamber is "improved", if I cannot find virgin 250 Savage brass to fireform. But for now, I am dealing with the standard 250 and should be able to proceed with the headspacing I have.