.280 AI controversy explained ...

[can1010]

I thought that this was settled science.
traditional is longer than SAAMI
use false shoulder if firing SAAMI brass in traditional chamber.
I talked to Dave Kiff years ago and he even admitted Nosler screwed up by being short causing all kings of confusion

 

[Pdvdh]

I've always thought one of the best things about math was the absence of smoke.

Is it your position that there is no difference between the two chambers? If so, what is the actual test you recommend to conclude there is no difference?

Bingo. Everyone's opinion is correct.

Only one set of headspace dimensions is correct. Yawn... yawn... and yawn some more.

Maybe Mr. Kiff will step forward to correct this lowly engineer. Or maybe I'll correct him... a second time.

 

[Pdvdh]

If your attitude was as above then I'm not surprised it turned personal.

Yes I have formed a position as every time I tested actual chambers, traditional and SAAMI, with gauges and try and find this magic .014 shorter chamber it vanishes in a cloud of mathematical smoke.

So you suggest resolving the issue by measuring a bunch of rifle chambers? That's how standards for headspace dimensions are established? No wonder you're confused. You think that's how Redding reached their determination prior to cutting a bunch of resizing dies for sale to their customers?

 

[woods]

 

[yawn]

I've always thought one of the best things about math was the absence of smoke.

Is it your position that there is no difference between the two chambers? If so, what is the actual test you recommend to conclude there is no difference?

Ha ha, depends on how good the maths is I suppose, one decimal point out of place can have amazing consequences.

Yes Edd that is my position.
Gunsmith talk has an example at the beginning of this thread. Showing both the SAAMI and traditional chambers then swapping the chamber gauges around proving they are actually the same. No one has yet pointed out where or how they are wrong.
I thought it was a little over complicated though and took a more basic approach.
This whole discussion is around the nosler spec being .014 shorter so if you use Nosler 280ai brass it in a traditional ackley chamber it will grow by .014 and maybe create case head separation issues.
Back in the beginning I was like a lot of guys just happily burning powder in my 280ai. Then I saw the alert that I was using the wrong brass for my traditional chamber. But I had no issues at all. The nosler brass wasnt gowing, in fact it was a little tight if anything and fired brass was the same base to shoulder length as new. So I rang cooper and confirmed I did indeed have a traditional chamber. But still that made no sense according to the -.014 theory. So after all the reading and internet chatter I bought a 280 rem go gauge and yes it confirmed it, its a correctly head spaced traditional ackley. I have checked more than a few 280i chambers now and results are always the same plus or minus a couple of thou.
So if nosler SAAMI brass does not gain any length in a traditional chamber, if the 280rem go gauge behaves the same in both SAAMI and traditial chambers how can there be a difference?
Again, ,these are just more words on the internet and wont convince anyone that has already made up their mind so don't believe me , test for yourselves, its not hard.
phorwath Im sorrry someone hurt your feelings on some other forum but it wasnt me and I think you would do better to drop the attitude.

 

[MSLRHunter]

Perhaps Cooper got it wrong and you actually have a SAAMI spec 280AI?

 

[Edd]

Yes Edd that is my position.
Gunsmith talk has an example at the beginning of this thread. Showing both the SAAMI and traditional chambers then swapping the chamber gauges around proving they are actually the same. No one has yet pointed out where or how they are wrong.

Your position is incorrect and so is the information in Gunsmith talk. Where or how they are wrong is simple. If they are swapping gauges between chambers and not showing a difference, the gauges are not made to the correct dimensions.

 

[yawn]

Perhaps Cooper got it wrong and you actually have a SAAMI spec 280AI?

You need to read my post again. I had it confirmed by cooper and then tested it my self with the correct gauge. It is a a true ackley.

Your position is incorrect and so is the information in Gunsmith talk. Where or how they are wrong is simple. If they are swapping gauges between chambers and not showing a difference, the gauges are not made to the correct dimensions.

You are missing the logic here. The gauges fit the chambers they were designated for perfectly, they also fit when swapped. Their comment section is still open in the article, challenge them on it.
You also have no explanation of my experience but please dont bother. Iv already said I dont expect people to believe me just because I post something. We are hard wired to cling to our first understanding of an issue and can take a lot of persuading to change. So once again Ill say test it for yourself.

 

[The Oregonian]

6 years ago as I was getting into precision, reloading, etc, this confusion kept me away from a 280AI...went with a 30-06. This year I got a 280AI and things were pretty simple as the ecosystem has migrated to the SAMMI spec....but this thread reminds me of why I passed a while back.

 

[Pdvdh]

phorwath I'm sorry someone hurt your feelings on some other forum but it wasn't me and I think you would do better to drop the attitude.

No need to express sorrow on my behalf. I wouldn't be boasting and challenging "experts" such as yourself, if my feelings had been hurt. You misunderstand. I'm high-fiving. Bragging. Boasting. No hurt feelings here. On top of the world. No pity party.

Weren't you the one that thought my post was "hilarious"? You must feel differently now, or why complain about attitude?

Hilarious is your suggestion that gauging chambers of unknown quality of manufacture will somehow provide a definitive design headspace dimension. There's only one correct dimension for Mr. Ackley's "traditional" 280 A.I. If you disagree with that statement, make that clear. Then we'll know you operate outside the stratosphere. If I was unable to derive the correct design headspace dimension mathematically, maybe I too would use some gauges of uncertain manufactured quality/accuracy. Difference is, I'd never consider the process to provide anything more than chamber measurements of unknown quality, using a gauge of uncertain accuracy. The only reason the uncertainty over the difference in headspace dimensions between the SAAMI and traditional 280 A.I. persists is because of posts from folks like you, unable to process the math.

I've committed myself to the correct headspace dimension for the traditional 280 A.I. Why don't you provide us with your headspace dimension for the traditional 280 A.I., and explain how you reached that determination? +/- 0.001" will suffice. Please don't refer us to other Forums, other posts, other "experts", such as the inaccurate Shooters' Forum. I'll be waiting, as your explanation is certain to be..., hilarious!

Until then, all your posts on the subject remain nothing more than yawners. You want to challenge my derived headspace dimension? Then commit yourself to a numerical headspace dimension, and let the fun to begin. Or, keep us yawning, yawning, and snoring with nothing more than opinion based on... others' opinions. You've committed to absolutely nothing. I'm game. Are you? I really doubt it... But I'm willing to spank, if you're willing to commit. It could even prove educational, if you're up to it.

 

[Pdvdh]

Yup. ~0.0142" difference.

That's brilliant! And too often, so true.

 

[yawn]

What I found hilarious was the dragging up of a five year old thread involving an issue that is little more than a light zephyr in an egg cup and has been done to death. . It was two lines with 24 words, not one of which referenced you or anything from your post so NO I didnt call you or your post anything, you have that completely wrong. I do however confess to getting a chuckle from your last post.
Yes there is only one correct dimension for Mr. Ackley's "traditional" 280 A.I. I have never said other wise. Its the constant in this discussion, the control. I understand it perfectly. It is the SAAMI spec that is and has always been in question.
I also understand the Maths , that image has been posted so many times now its fading and no I wont argue maths because I agree it shows a .014 difference. I believed it, its what got me into this conversation many years ago. But I'm no longer interested in the maths, the theory. That's the beginning of the process, what normally follows is the experiment that proves or disproves the theory, the practical, in this case the physical chamber. Heres the issue, the physical SAAMI chamber when constructed properly and head spaced correctly is not a clean translation of the maths we are seeing , there is a disconnect somewhere, the .014 difference from the original ackley is not there. Now you claim that its all unknown chambers and gauges , and gunsmithtalk is wrong and Im wrong and no one understands but for that to be relevant the chambers from cooper, kimber and the customs Iv checked , the dies , gauges, the gear used by gunsmithtalk etc and all the nosler brass would have to not only have a magic error but the same error of the same amount possibly working in two differnt dimensins at the same time. . What are the chances?
But of course that must be the case because, well, you've done the maths.
So carry on. Ridicule seems to be your best debating technique so let rip.
As Iv said before, Im not interested in convincing anyone of anything, Im simply putting out what Iv found and suggesting people check for themselves.

Merry Christmas and a happy new year to all.

 

[Pdvdh]

The SAAMI 280 Ackley Improved headspace dimension is set in stone by the SAAMI standard for that cartridge. By definition that dimension is always correct, never wrong or flawed. It remains the same unless/until SAAMI formally changes it. Any chamber cut outside those SAAMI headspace tolerances and provided for use is defective, by definition. 1st failure = manufacture of a defective rifle chamber. 2nd failure = the defect escaping detection with a QA/QC inspection process.

Therefore the only headspace dimension up for any debate is that of the original, (commonly called the "traditional") 280 A.I. cartridge. No SAAMI standard was ever established for it, so it's not locked down, codified in concrete. Which is why I calculated that headspace for the "traditional" cartridge following the P.O. Ackley handbook standard for establishing Ackley headspace. The headspace dimension I calculated in this manner is identical to Redding's website description. Undoubtedly because Redding would have completed the identical mathematical analysis before manufacturing their very first 280 Rem Imp 40 Deg resizing die.

Math produces all these design specifications and construction drawings and standards. And now your pooh-poohing the math that creates the headspace dimensions as an inferior method for identifying the proper headspace dimensions? Inferior to what? Go gauges?

The gauges you reccomend be purchased and used are designed to ensure chambers are cut to design specifications. Not to disprove or change any cartridges' design headspace dimension. Proper gauges support the QA/QC inspection effort to ensure the 'design' headspace tolerances are met before the rifle leaves the shop/plant.

I cannot tell you why a rifle chamber gets cut out of spec. Who could? But with properly constructed gauges, even this non-gunsmith engineer could identify a chamber cut with defective headspace. Chambers cut with defective headspace don't create or change the design headspace standards. Neither will headspace measurements on those defective chambers.

I thought the purpose of the thread was identification of proper headspace dimension for the "traditional", versus the SAAMI, 280 improved cartridges. There are headspace standards for both cartridges.

If the purpose of the thread was instructional on proper chamber headspace measurement tools and methods, then measure away. But don't expect any measurement, opinion, or preference, to change the 'design' headspace dimension/standard for either cartridge.