257 Roberts Ackley Improved Fire-forming

Discussion in 'The Ammo & Reloading Forum' started by Freebore, Apr 19, 2009.

  1. Freebore

    Freebore Active Member

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    Hi, (new to this forum)

    Anyone have experience fireforming brass for the Ackley 257 Roberts Improved cases. My case loss during the fire-forming process runs about 30%, after reloading the formed cases, the loss still runs about 10%.

    Tried beefing up the standard factory Roberts loads and it did help cases life, but case separation still occurs.

    Checked headspace and its good on the Go guage, very tight on the No-Go guage and N0-G0 on the Field guage. I neck size only so as not to move the shoulder back.

    Maybe its just the price you pay for the extra FPS

    Any thoughts ??...anyone
     
    Last edited: Apr 19, 2009
  2. Terry_P

    Terry_P New Member

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    Where are you getting the problems? Do you have any pictures. There is 257 Robers +P brass out there and I don't know if that would be any better to use. How many times have the cases been previously reloaded before fire forming?
     

  3. Bindernut

    Bindernut Well-Known Member

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    Not a .257 AI, but I have done some fire-forming for the 6mm Remington (.244 Rem) Ackley...

    I did lose about 5 out of a lot of 100 brand new cases, but these were shoulder blow-outs instead of head separations. I suspect the new brass (Remington brand) was a little too brittle and I should've annealed the shoulder area before fire-forming.
    I ran the virgin brass through the standard 6mm FL sizing die just far enough to neck-size the brass and then used starting loads for the fire-forming shots.

    Are you using virgin brass for the fire-forming? Are you using just a neck-sizing die or a full-length die backed off a bit? (a neck-sizing die is preferred...especially on a straight-body case like the Ackleys).
    Have you done a chamber cast of the chamber and your die to do some mic measurements?
    And yes, some pics of your cases might help track down a problem too.


    I don't have a lot of experience with Ackleys or other Improved cases, but it kinda sounds like your chamber might be cut a little too deep? You shouldn't be able to close the action at all with the no-go gauge (very tight means that you've got a little too much chamber).
     
    Last edited: Apr 19, 2009
  4. Freebore

    Freebore Active Member

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    The problem (when it occurs) is case separation about 1/2 inch from the case head. I have not tried any of the +P brass, but might be worth a try. In the past case failure has been initially on new brass, and then the first time after fire-forming. I expect some cases (different lots) may vary as to wall thicknes, I currently have about 250 cases that work OK

    Thanks for the input
     
  5. Freebore

    Freebore Active Member

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  6. Freebore

    Freebore Active Member

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    Hi,

    The brass used was new (WW), after fire-forming I neck size only. I have not done a chamber cast (may be my next step). I belive that the chamber is slightly over standard length. I'm sure there is also variation in case wall thickness from lot to lot due to the fact that failures tend to be grouped. I discussed this issue to some length with my local gunsmith and he feels that fire-forming is pretty rough on cases to begin with, and any additional tolerances will produce more failures. he aslo feels that once a case if formed with no failure marks (bright ring) they should perform OK, I have found this to be true, I have some fired cases that have reloaded quite a few times.

    I appreciate your response and value your comments.

    Thanks again for your feedback and input
    Thanks for your input
     
  7. Bindernut

    Bindernut Well-Known Member

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    Yeah, your smith is right about fireforming being a little more abusive to the brass...after all you are stretching it quite a bit more than it is normally designed to expand in the chamber that it was formed for. I think you might have better luck if the headspace wasn't quite as long though.

    Annealing the neck and shoulder might help although the WW brass that i've used is pretty soft compared to the Rem brass that I had problems with...I've noticed that Rem brass will split-neck with fewer loadings than WW brass with the same loads in both my .25-06 or my dad's .270.

    Another thing you might want to try for forming virgin brass...
    If you've got any 6.5 (.264) dies, neck your brass up to .264 using just the expander ball. Then run them through your neck sizer die to swage MOST of the neck back down to .257, leaving a small "false shoulder" to help headspace the cases in your long chamber. Trial and error to get that shoulder in the right spot so the action will close snugly on the brass and you will cut down on the amount of head separations when fireforming. I learned that trick from a local shooter here that has a 6x57mm wildcat that has a deeper chamber than the 7x57 that he forms it's brass from. The Hornady tapered expander is supposed to work better than a regular expander ball for this and I'd definitely anneal the case necks first.

    Good luck!
    I've been looking at one of my old M96 Swedes, that has excessive headspace and was already bubba-ized by a wannabe 'smith, with the thoughts of doing an AI version of the 6.5x55 or 6.5x57, but haven't decided if I want to sink the time into the project.
     
    Last edited: Apr 21, 2009
  8. Freebore

    Freebore Active Member

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    Thanks for the info, that sounds like an excellent way to reform the cases. I think I have a set 264 WM dies around here somewhere. I also thought of making new cases from new unformed brass.,

    Thanks again
     
  9. Newtire

    Newtire New Member

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    Hi, I am new to this forum as of today but saw the post on a search on the .257 Ackley. I found out a few things in fireforming cases and weighing Remington against Winchester. Remington has less inner case volume than Winchester and some of the loads I developed in Winchester cases showed signs of loose primer pockets when loaded into Remington cases. The once fired cases that I tried to fireform split a few necks until I decided to anneal them. I did most of the fireforming with the RCBS 120 grain bullet under 23 grains of RX-7. I wound up with a lot of cases this way without worrying about wearing out the bore.

    I have been having fun with this caliber and it really isn't too hard to load for. Plus, any .244/6mm Remington case can be firformed into it also as well as the Robert's parent cartridge, the 7X57. No shortage of brass for this thing. No worries about chambering one of those fireformed cases in a .244/6mm or 7 X 57 either unless you used a sledgehammer to close the bolt cause it isn't going to fit.

    Like I mentioned, it's best to use new brass if you have it but annealing once fired stuff worked great for me.
     
  10. Freebore

    Freebore Active Member

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    Hi Newtire (and welcome to the forum)

    I agree on the WW vs Rem cases, I've found Remington brass is touchy in some situations, using identical loads in both brands, can show signs of higher pressures in the Remington cases.

    The small percentages of case failures I do see in the .257, I now consider collateral damage, the rifle still performs way above your average factory gun. Even when case seperation occurs, accuracy doesn't seem to be affected.

    P.O. Ackley did a lot to improved standard cartridges, and .257 was probably by far his most popular.

    A pic of a more successful FF
     

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