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    catgunguycatgunguy Member Posts: 6,089
    edited November -1
    Well I guess that is that. Controversy over. [;)][8D]
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    CheechakoCheechako Member Posts: 563 ✭✭✭✭
    edited November -1
    I've owned a couple of 280 AI rifles that I chambered myself and, truth be told, I did not realize there was a controversy.

    Dang it! I missed it!

    Ray
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    MIKE WISKEYMIKE WISKEY Member, Moderator Posts: 9,986 ******
    edited November -1
    damn, I missed one again.......same could be said of any of the Ackley cals.
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    FEENIXFEENIX Member Posts: 10,559 ✭✭✭
    edited November -1
    quote:Originally posted by Cheechako
    I've owned a couple of 280 AI rifles that I chambered myself and, truth be told, I did not realize there was a controversy.

    Dang it! I missed it!

    Ray


    Yep, I know what you mean!

    C&P extract from one http://www.redding-reloading.com/tec...-280-changes:
    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.
    
    
    I posted it on another site and it was unbelievable what kind of information it came out.

    They provided of pictures of flattened primers. I am still waiting for response(s) on what kind of pressure they are generating out of their loads. [:p]

    I don't own a .280 AI but I loaded one for a friend's Ruger M77 MKII in .280 Rem accurized by by Brad Stair of Wasatch Precision Arms (WPA) in UT.. The hottest load was with 60gr H4831SC, 140gr NAB, BR2, Nosler AI brass, and .005" off the lands ... no pressure signs, no flattened primers. I didn't get a chance to further fine tune it for him but he was happy at under an inch group at 200 yards.
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    nononsensenononsense Member Posts: 10,928 ✭✭✭✭
    edited November -1
    FEENIX,

    I'm glad you came back to explain just what this is all about. Your link doesn't work so here is the 'FAQ' and the whole link:

    http://redding-reloading.com/tech-line-a-tips-faqs/133-280-changes

    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 www.redding-reloading.com.

    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.
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    FEENIXFEENIX Member Posts: 10,559 ✭✭✭
    edited November -1
    nononsense,

    Many thanks for the link, any word of wisdom on the video claim?
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    nononsensenononsense Member Posts: 10,928 ✭✭✭✭
    edited November -1
    FEENIX,

    quote:...any word of wisdom on the video claim?

    One word?

    No, but I can conjure up about 3-4,000 in one sitting just to try to clear up the BS that Redding and SAAMI have given us. The problem is that this amount of writing, to do correctly, could take me a couple of hours which I simply don't have these days. Sorry.

    In short though, I measure everything before I start a chamber, this includes the reamer, headspace gauge and brass. Why? Too many stupid people in the manufacturing end of this business who don't want to afford Quality Control. Example:

    I just sent 4 brand new reamers ($700.00) back to the maker because they were absolutely wrong according to my prints. They pulled the wrong prints from file instead of using the ones I specified in writing. Then to compound the error, they intentionally neglected to measure the reamers and check the prints I asked for.

    I've been cutting chambers for Ackley cartridges for a long time. I've never had a failure of any type occur from any of the 200+ Ackley chambers. I follow Ackley's guidelines and I measure everything, twice if necessary. I also test fire every one at least once then measure the case again.

    There never was a controversy and there never will be when the rules are followed by people that have been trained properly.

    Best.
  • Options
    FEENIXFEENIX Member Posts: 10,559 ✭✭✭
    edited November -1
    quote:Originally posted by nononsense
    FEENIX,

    quote:...any word of wisdom on the video claim?

    One word?

    No, but I can conjure up about 3-4,000 in one sitting just to try to clear up the BS that Redding and SAAMI have given us. The problem is that this amount of writing, to do correctly, could take me a couple of hours which I simply don't have these days. Sorry.

    In short though, I measure everything before I start a chamber, this includes the reamer, headspace gauge and brass. Why? Too many stupid people in the manufacturing end of this business who don't want to afford Quality Control. Example:

    I just sent 4 brand new reamers ($700.00) back to the maker because they were absolutely wrong according to my prints. They pulled the wrong prints from file instead of using the ones I specified in writing. Then to compound the error, they intentionally neglected to measure the reamers and check the prints I asked for.

    I've been cutting chambers for Ackley cartridges for a long time. I've never had a failure of any type occur from any of the 200+ Ackley chambers. I follow Ackley's guidelines and I measure everything, twice if necessary. I also test fire every one at least once then measure the case again.

    There never was a controversy and there never will be when the rules are followed by people that have been trained properly.

    Best.






    You know I always respect and value your opinion, vast experience, and candor but most especially your willingness to share them to help others.

    Thanks again!
  • Options
    nononsensenononsense Member Posts: 10,928 ✭✭✭✭
    edited November -1
    FEENIX,

    You are very kind.

    I was re-reading your post which stated:

    quote:I posted it on another site and it was unbelievable what kind of information it came out.

    They provided of pictures of flattened primers. I am still waiting for response(s) on what kind of pressure they are generating out of their loads.

    I had to review some of the commentaries I have saved to a file from so many websites, regarding Ackley chambers, improved velocity and pressure. Some of the comments made are truly stupid and grossly uninformed (yet authoritatively expressed) while others have the right idea but lack experience.

    Flattened primers will occur from two situations:

    1) Over-pressure. (as most folks assume with this cartridge)

    2) Improperly measured and cut chamber.

    The #2 is what concerns us with this commentary because it is the improper chamber which often shows flattened primers which are interpreted as being a function of high pressure.

    What actually happens in the improper chamber is that the firing pin strikes the primer and pushes the entire cartridge forward. As the powder ignites and the pressure builds, the cartridge grips the chamber walls then expands backwards, pushing the primer out slightly then flattening the primer against the bolt face. This is what folks so wrongly interpret as being a problem of high pressure.

    Low pressure loads will often show a similar characteristic.

    We can't avoid #1 though because it can be a symptom with Ackley chambers unfortunately.

    Ackley cartridges and chambers do not show gradual changes in pressure as do other standardized cartridges. This is due in part to the straighter case walls gripping the chamber walls. When the folks shooting Ackley cartridges see pressure signs, it's usually startling and unexpected. It's best to check with others of greater experience for load data or do your load development using smaller increments.

    quote:The hottest load was with 60gr H4831SC, 140gr NAB, BR2, Nosler AI brass, and .005" off the lands ... no pressure signs

    It shouldn't show any signs of pressure simply because it is a low pressure load.

    Best.
  • Options
    FEENIXFEENIX Member Posts: 10,559 ✭✭✭
    edited November -1
    quote:Originally posted by nononsense
    FEENIX,

    You are very kind.

    I was re-reading your post which stated:

    quote:I posted it on another site and it was unbelievable what kind of information it came out.

    They provided of pictures of flattened primers. I am still waiting for response(s) on what kind of pressure they are generating out of their loads.

    I had to review some of the commentaries I have saved to a file from so many websites, regarding Ackley chambers, improved velocity and pressure. Some of the comments made are truly stupid and grossly uninformed (yet authoritatively expressed) while others have the right idea but lack experience.

    Flattened primers will occur from two situations:

    1) Over-pressure. (as most folks assume with this cartridge)

    2) Improperly measured and cut chamber.

    The #2 is what concerns us with this commentary because it is the improper chamber which often shows flattened primers which are interpreted as being a function of high pressure.

    What actually happens in the improper chamber is that the firing pin strikes the primer and pushes the entire cartridge forward. As the powder ignites and the pressure builds, the cartridge grips the chamber walls then expands backwards, pushing the primer out slightly then flattening the primer against the bolt face. This is what folks so wrongly interpret as being a problem of high pressure.

    Low pressure loads will often show a similar characteristic.

    We can't avoid #1 though because it can be a symptom with Ackley chambers unfortunately.

    Ackley cartridges and chambers do not show gradual changes in pressure as do other standardized cartridges. This is due in part to the straighter case walls gripping the chamber walls. When the folks shooting Ackley cartridges see pressure signs, it's usually startling and unexpected. It's best to check with others of greater experience for load data or do your load development using smaller increments.

    quote:The hottest load was with 60gr H4831SC, 140gr NAB, BR2, Nosler AI brass, and .005" off the lands ... no pressure signs

    It shouldn't show any signs of pressure simply because it is a low pressure load.

    Best.




    Like_zps00ba1bd0.jpg

    Cheers!
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    sandwarriorsandwarrior Member Posts: 5,453 ✭✭✭
    edited November -1
    As nononsense pointed out, Ackley cartridges often don't show pressure signs until they are over-pressure. The suddeness with which the signs come on seems to have most of us baffled.

    FWIW, my $.02 on it is that if you were too look at powder and a burning rate, you would find that even though it is much slower, it still acts like the explosives I dealt with in the U.S. Army. Powder burning at roughly 20k fps, and a common explosive for military use, TNT, about 22k fps. (Keep in mind powder burn speed does not directly correlate to bullet velocity. Pressure, and timing of pressure applied, are what does that.)

    In any case, the principle of making the substances work is to contain and direct the forces they produce. If you were to allow powder to burn in a pile, it pretty much goes PHffft...and it's done. Set of a stick of TNT and goes "bang!" pretty loud, but again doesn't really do much. Pack the explosive in such a way as it works against an intended item to be destroyed and pack something behind it, thereby containing the blast and it does an incredible amount of work for such a small amount of substance. The same can be said about powder. Put it in a case and ignite it, and you already have improved efficiency %20,000. Now further contain the blast with a bottle-neck and it's even more efficient. Finally, move that bottle neck to 40 added: Degree where the blast is REALLY contained and you have maximized what that amount of powder can do for it's given volume. A note here: most of the newer competition rounds use a 30 to 30-something degree shoulder

    In each case, as you increase the containment of the substance as it ignites, it increases the burn and puts out more energy in a given amount of time. The problem now is, "Can the pressure given off by the ignition of this substance go someplace?" You want to restrict the outlet enough to maximize sending a projectile downrange. But, you don't want to restrict it so much the pressure has no where to go and builds too fast and causes too fast of a detonation.

    This is where I look at the shoulder angle of a bottleneck case as to whether the case is efficient. The powder stack is pushed foward as pressure builds from the rear of the case. In the steeper shouldered cases, especially the wider bodied cases, there is too much volume trying to get out of 'not enough hole'. The pressure then increases exponentially above what it should. Thus, the effectiveness of steepening the shoulder angle is lost. This is highlighted by a .223 AI, which is an improvement. A .22-250 which is on the verge of too much, and a .223 WSSM, corrected myself: .223 WSSM AI which is insane.

    Something to think about with the Ackley cases. It's not just about the improved capacity, but rather how it changes the burn characteristics of given powders that we work with all the time. Get near the top and they tend to cook off a lot faster than we expect.
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    JustCJustC Member Posts: 16,056 ✭✭✭
    edited November -1
    I can attest to the lack of gradual pressure signs. I have a 6.5x55AI, 6.5-06AI, and 280AI. I got lucky and ran my 6.5-06AI across a chrono because that nagging little voice was saying something about how much powder I was burning and not seeing any pressure signs. Well, do the math and figure how much pressure it takes to get a 140gr pill over the chrono at ~3200fps from a 26" barrel in a NON-magnum cartridge[:0][B)] thank god for the chrono AND that nagging little voice....

    always run Ackley or any other Improved load ladders over the chrono for a safety check[;)]
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