.280 AI controversy explained ...

Discussion in 'Reloading' started by FEENIX, Aug 4, 2013.

  1. FEENIX

    FEENIX Well-Known Member

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    [ame="http://www.youtube.com/watch?v=Vlskn2CE7-Y"]280 Ackley Improved Controversy Explained - YouTube[/ame]
     

  2. woods

    woods Well-Known Member

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    Bullchips!!
     

  3. FEENIX

    FEENIX Well-Known Member

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    Please elaborate, comment as such is no help to anyone! If you have something constructive or helpful information, please by all means share.
     
  4. woods

    woods Well-Known Member

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    280 Ackley Improved Alert | GunsmithTalk

    January 13, 2010 · 10:28 pm

    ↓ Jump to Comments

    280 Ackley Improved Alert


    A few years back Nosler decided to bring the 280 Ackley Improved into their list of custom brass and rifles. In order to do this they wanted to take the 280 AI to SAAMI and have it standardized.

    Part of the process of standardizing the cartridge was for Nosler to see if other manufacturers had worked with it. They found that Remington had been chambering the 280 in their custom shop. Now here is where the alert comes in. Remington’s Custom Shop chose to shorten the headspace on the venerable design by .014″. When Nosler sent drawings to SAAMI they picked up that number as well.

    So by a vote of the members of SAAMI the commercial established specifications for the 280 Ackley were changed from the original design. The reason reported for this change is that Remington believed it was necessary in order for factory 280 Remington ammunition to be fireformed safely in an Ackley chamber. Apparently they did not know that Ackley was the single most successful wildcatter of the 20th century. While he was not the first guy to create and “improved” design, he was the first to standardize the idea and create a safe method of fireforming factory ammo in improved chambers.

    Ackley’s method was simple, he simply used a headspace gauge .004″ shorter than the factory case. This shorter headspace assured that the cartridge would be held tight between the bolt face and the junction of the neck and shoulder of the chamber during fire forming. Ackley’s method worked fine for more than 50 years before these alterations to his design were made.

    Bottom line for anyone who now works with the 280 Ackley Improved you must decide which version of the chamber you will use; the SAAMI or the Ackley; you cannot safely use the Nosler brass in a traditional Ackley chamber, although it would still be safe to fire form factory ammo in a SAAMI/Nosler chamber.

    Compare the length of these two designs.

    UPDATE: See this post for new information

    [​IMG]


    Now I have a 280AI that was rebarreled by Hart before the SAAMI dimensions were made official. Before all this information became available I purchased a box of Nosler 280AI brass. I had severely flattened primers (fire forming less than max load)

    [​IMG]

    Measuring with the Hornady comparator to the shoulder datum the measurements on the Nosler 280AI brass going from new brass to once fired was:

    new case - 2.1350" (subtracting of the comparator and holder when zeroed at 2")
    once fired - 2.1500" (neck size with Lee Collet)
    twice fired - 2.1520" (neck size with Lee Collet, very slight crush fit, fully expanded)

    So the Nosler 280AI brass expanded .017" at the shoulder

    When I fire form Nosler 280 Remington caliber brass I do not get flattened primers. Obviously I can not take measurements on the datum line with the Hornady comparator on a 280 Remington case, so the final results are all the data I have.

    Now this is in MY rifle chambered by a reputable company Hart

    [​IMG]

    and it has the very remote possibility of being the only one in the world if you so choose to believe that has this chamber

    But to have someone take 2 reamers, origins unknown, and say that there is NO controversy of anything to be concerned about is LUDICROUS

    IMO YMMV
     
  5. woods

    woods Well-Known Member

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    280 Ackley Improved vs. 280 Rem. Improved 40 Degree | Redding Reloading Equipment: reloading equipment for rifles, handguns, pistols, revolvers and SAECO bullet casting equipment

    280 Ackley Improved vs. 280 Rem. Improved 40 Degree
    The SAAMI spec cartridge carries the approved name of " 280 Ackley Improved " .
    The older wildcat has several names including 280 Ackley Improved 40°, 280 Rem Improved 40°, 280 Imp 40°, 280 Ackley, 280 Rem Imp, and more.
    The SAAMI spec 280 Ackley Improved chamber is .014 inches shorter at the datum line headspace dimension than the traditionally accepted wildcat chamber spec as previously produced.
    Our current production dies are for chambers that are cut to the SAAMI specification and are stamped "280 Ackley Imp".
    Any Redding dies made before 2011 are stamped " 280 Rem Imp 40° " and are built to the originally accepted wildcat specs.
    These older dies will not bump the shoulder of cases for a SAAMI chamber. In other words, the old dies are too deep for the current SAAMI chamber.
    Redding makes a Competition shellholder that is .014 deeper than the standard #1 shellholder so the owner of a wildcat chamber can use the current SAAMI spec dies for safe resizing.

    Failing to use this shellholder or to back the die away from a standard shellholder by a minimum of 0.014" will result in too much shoulder bump which may create an unsafe, excessive headspace condition when fired in a traditionally dimensioned wildcat chamber.

    To find the die part numbers for a current production SAAMI spec. rifle, please download our current catalog as a .pdf from Home | Redding Reloading Equipment: reloading equipment for rifles, handguns, pistols, revolvers and SAECO bullet casting equipment.
    You will find these dies listed in Series C and Category II. Limited quantities of the traditional wildcat dies which are marked " 280 Rem Imp 40° " are available at Custom Series Die prices.

    Bottom line, don't rely on only the web.
    The names many list for this cartridge can be misleading.
    Remember, they are wildcat cartridges and adhere to no formal standard.

    Note: Any dies that Redding makes for SAAMI approved cartridges are always stamped with the SAAMI approved name or abbreviation.



    I amend my previous first post

    HORSEHOCKEY!
     
  6. woods

    woods Well-Known Member

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    New and Improved: The .280 Ackley Improved - RifleShooter

    For reasons too lengthy to go into here, the headspace dimension for the .280 Ackley Improved cartridge approved by SAAMI and introduced by Nosler turned out to be shorter than headspace gauge manufacturers had established for the original Ackley version. Some reloading die makers have responded by offering different die sets for the two.

    Dies made by Redding for the Ackley version prior to 2011 were marked “280 Rem Imp 40 Degrees.” They are still available. Dies for the Nosler version are marked “280 Ackley Imp,” which is the SAAMI-approved abbreviation. In the past, RCBS dies for the Ackley cartridge were marked “280 Imp 40 Degrees,” and they will continue to be so while dies for the SAAMI/Nosler version will be marked “280 Ackley Imp.”

    The important difference between the two die sets is in their full-length resizers. Since headspace dimension of the SAAMI cartridge is shorter, the shoulder in a die reamed for the Ackley cartridge won’t make contact with the shoulder of the case.

    If a die reamed for the SAAMI version is screwed into the press far enough to make contact with the shellholder and used to resize a case fired in a rifle chambered for Ackley’s version, the shoulder will be set back for an increase in headspace. But it can be used by screwing the die in just far enough to lightly bump back the shoulder enough for trouble-free chambering of the cartridge. So when purchasing reloading dies for a rifle it is important to know which version of the .280 AI it is chambered for.

    If other companies introduce rifles in .280 Ackley Improved, they will likely be chambered for the SAAMI version, and Nosler cases and ammunition will surely work fine in them. But since the original .280 Ackley Improved is a wildcat, gunsmiths who have chambered rifles for it over the past 65 years or so have not always agreed on precisely how deeply the chamber should be reamed.

    So to be on the safe side, it is not a bad idea to have the headspace of a rifle chambered for Ackley’s version checked by a gunsmith to determine its suitability with Nosler cases and ammunition. Kenny Jarrett, who has chambered more than 1,000 rifles for the original Ackley version, agrees with my opinion. So does Dave Kiff of Pacific Tool & Gauge, which makes chamber reamers and headspace gauges for both versions.



    Personally I don't use go-no go-field gauges as used by gunsmiths and IMO they have little use for us as reloaders. To say that no problem was created or does not exist is again

    DONKEYDUNG!
     
  7. FEENIX

    FEENIX Well-Known Member

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    Good, that's much better ... now let the end-users heed and learn from all the information available.
     
  8. MudRunner2005

    MudRunner2005 Well-Known Member

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    When you were naming off the nom de guerres, you forgot 7mm Remington Express & 7mm Express.
     
  9. yawn

    yawn Well-Known Member

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    Well Im still undecided. Woods that link in your post that you are using to support the affirmative position is from the same site/people that made the video that you claim is " bull chips" If you click on the link beside the illustration it takes you to their conclusion after doing some actual testing with both reamers. The other info you posted is all based on the same assumption that the datum for measuring both chambers is exactly the same so still nothing to refute the "different datum" position taken by the makers of the video. Yes your individual chamber shows some growth from nosler brass but then mine does not so we have more conflicting evidence.
    I'm not confident basing the discussion simply on the reputation of the gun builder as proof that my chamber is correct as every human makes an error at times so the simplest way I see to prove this one way or the other is to try both the original ackley and the saami spec go/no go gauges in my chamber. I have been trying to do this for some time and almost have the necessary bits together and Ill post my results as soon as I can. That will tell me if I have an original ackley as claimed by the builder , a new saami or both if there is actually no difference. Im not betting on any one outcome :).
    Something else I was wondering about, the original ackley design was .004shorter than the parent case. If the saami is a further .014 shorter then the saami 280ai chamber would be .018 shorter than standard 280 rem brass/ factory 280rem ammo and would be quite hard to chamber and close the bolt. Has anyone seen this with a new saami chamber?
    But how much of an issue is it if there is a difference? I dont see growing reports of case head seperation or any problems that could be related to excessive headsapce and this has been around for 5+ years?
     
  10. cockcroft

    cockcroft Well-Known Member

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    Five or six years ago I had a 280 AI built using a reamer and go gauge that was made many years before. My guess was minimum 10 to 15 years. Bought Nosler 280 AI brass and fire formed 50 pcs. Then went to reload them and my Redding FL die didn't even touch the shoulder area. Measured the cases and they were 14 thou longer then the new Nosler AI brass. Ended up milling the top of the shell holder down until I got the resizing dimension I wanted.
    I did not watch the video, just read the posts and thought I would throw in my experience with an older reamer/gauge and new brass specs.
    Mike
     
  11. woods

    woods Well-Known Member

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    Well my point is this; in the articles I linked to, Gunsmith Talk, Redding and Rifle Shooter they all talk about and admit that the SAAMI version has shorter headspace. My experience and Cockcroft's and others I have talked to have the same issue. Yes the same gunsmith posted the video but after several posts chronicling the .014" difference. Did he recant that or explain how he could repeatedly define the difference and then post the video? Does the video go counter to the previous explanation?

    Now because of some smoke and mirrors magic trick with gunsmith gauges we are supposed to just ignore that difference? Where did that "traditional" reamer come from? Does it match all the old reamers or even a few? Is some warehouse worker gonna say "OH! You meant the OLD reamer like we used to use 15 years ago!" I am not going to buy gunsmith gauges to check it out. I get enough information from what I have.

    For someone to tell me that there is not a significant change in headspace on a new piece of Nosler 280AI brass and my chamber is speaking nonsense. Now how that would fit in with his gunsmith headspace gauges, I have no idea and really don't care.
     
  12. yawn

    yawn Well-Known Member

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    They are some of the questions we are looking to answer arnt they?
    I see the orignal post by gun talk as being along the same lines as everything else based on diagrams and measuerments . Then it seems they did some actual testing and found no difference. I dont see how thats " smoke and mirrors"
    I also don't see anyone telling you that there is no difference between your chamber nosler ai brass, youve proven that there is . The questions are do you have an exact original ackley chamber or is it a little out of spec? Do I have an original ackley chamber as Iv been told or has the builder got it wrong and I have an saami chamber? Is there in fact a third addition to the discussion where the now saami spec was adopted by gun builders long before the saami registered it therefore clouding the waters even more?
    Cockrofts report is interesting as his cases got longer by .014 but he still had to shave the case holder to get the shoulder contact as if the cases where still a little short?

    Its all interesting but end of the day if we check headspace,fireform correctly and set the sizing die up properly then its a non issue isnt it?
     
  13. FEENIX

    FEENIX Well-Known Member

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    I agree!

    C&P extract from one of the links (http://www.redding-reloading.com/tech-line-a-tips-faqs/133-280-changes):

     
  14. Tnwhip

    Tnwhip Well-Known Member

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    When I had my barrel chambered for the 280 Ackley. It was the old original ackley. I thought I would be smart and I bought Nosler 280 Ackley brass. I loaded some, one g from 280 Rem. max load and iit flatened the primer really bad. I checked and the head space was .014 longer than the Nosler brass. Then I started checking and found out what Nosler did. Are they stupid or what? No big deal now that I know what is going on. Just have to fire form my brass even if it is Nosler . Just out of spite I will never buy another box of Nosler brass just because of what they did. Got to fire form anyway.