.257 Ackley Improved

Discussion in 'Up To .375' started by MikeDeltaFoxtrot, Jan 1, 2018.

  1. MikeDeltaFoxtrot

    MikeDeltaFoxtrot AH Veteran

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    A good friend of mine who is not a reloader has a nice rifle (Winchester M70) that was originally chambered in .257 Roberts, but he had it reamed out to .257 Ackley Improved. He has had it for years and as never had a good source for ammo. I am going to work up a load for him, probably using Barnes 100 gr. TSX boat tails. The Barnes manual show loads up to 3200 fps which is impressive, and will likely make a good white tail load.

    I understand that typically, .257 AI brass is fire formed by shooting .257 Roberts loads in an AI chamber. In the interest or moving things along, I'd like to buy some .257 AI brass already formed. Does anyone know of a source for such?

    Thanks.
     
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  2. Bullthrower338

    Bullthrower338 AH ENABLER AH Legend

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    I would recommend fireforming for that particular chamber. Follow load data for the standard 257 Roberts, seat bullet out to the lands to hold case head against the bolt face. You will separate cases if there is room for movement. I use 4895 when fireforming the 257AI. I would stay away from trying to buy cases that have already been fireformed due to the deviations in chambers.
    Cheers,
    Cody
     
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  3. dchamp

    dchamp AH Veteran

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    I don't know of anybody making AI brass for any caliber other than the .280 Remington AI. If he didn't save or doesn't have any fire formed brass then I would suggest he find a factory load that shoots well in his rifle, buy a 100 rounds, use it and then start the reloading process. There are methods for fire forming without making up fully loaded cartridges though but it will take a little research. Also you might see if you can find a copy of P.O. Ackley's Handbook for Shooters and Reloaders.

    One thing I would do before getting to involved is check the head space. The neck shoulder junction is the same in the standard cartridge and the AI cartridge. When the new chamber is cut for the AI you will find that the barrel is set back a little. If not done properly will cause head space issues. Good Luck
     

  4. ChrisG

    ChrisG AH Fanatic

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    Like dchamp said, no one really makes AI brass. Its allure is the fact that it is kind of a wildcat. I say kind of because Ackley Improved is more of a verb than a noun. One could almost say "I've AI'd my (insert cartridge here)." As such, you will need to fireform it. The easiest way is to buy brand new .257 Roberts brass, load about 10 grains of Blue dot into the bottom, put a cotton ball on top of that, then fill the rest of the case with cream of wheat leaving the neck mostly free and fillin it with cotton and soaking that with paraffin wax to hold the cream of wheat in place. fire these and they should blow out the shoulders nicely. try this with one load. If it doesn't fully form the shoulder, go up a little bit in the charge weight until you get nice clean shoulders. Then you have ready-to-go AI brass that is essentially brand new!
     
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  5. elmerfudd555

    elmerfudd555 AH Senior Member

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    Bullthrower has it right. Starting loads of 4895 with bullet out against lands will fire form the cases. Strongly suggest you get a Hornady case comparator to assist in setting up your sizing die. This will keep you from excessively setting the case shoulder back each time you resize and will extend case life as well as help with accuracy.

    I use the .257 100 grain TSX and TTSX extensively in my 257 WBY and love the performance.
     

  6. PARA45

    PARA45 AH Fanatic

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  7. Ridgewalker

    Ridgewalker AH ENABLER LIFETIME BRONZE BENEFACTOR AH Legend

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    Hopefully his chamber was reamed by using specs of what ever brand dies you have. Unfortunately there’s a risk that the dies and chambers are not identical. Historical issue with Ackley Improved cartridges. That said, if all goes well, I’d only neck size once they are fire formed. It should be an excellent deer cartridge!
    I have Ackley’s books, and would be happy to email you a photo of his loads, but the powders have all changed since he loaded them. Probably not valid now.
    Best of luck!
     
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  8. MikeDeltaFoxtrot

    MikeDeltaFoxtrot AH Veteran

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    Thanks to all for the excellent information.
     

  9. PaulT

    PaulT AH Elite

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    I have a wild-cat center-fire rifle in true .50 caliber where projectiles are limited and expensive.

    Rather than shooting projectiles to fire-form cases I use a very mild dose of pistol powder held down with a wad of tissue paper then a column of corn meal is packed down in the case above the charge of pistol powder and a spit-wet wad of tissue seals the case neck.
    This charge, when fired, forms my cases to within 98% of the true dimension and close enough to load with hunting loads, after-which the first true firing the case is fully formed.

    I do not know if this method is applicable in your case but if it is it would be well worth investigating as it negates the need to shoot bullets down the barrel thereby limiting wear on the gun and un-necessary expense.

    Worth looking in to.
     

  10. Ray B

    Ray B AH Elite

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    The advantage of an "improved" case over a "wildcat" case is that the improved (if done properly) can fire factory cases and by firing, forms them to the improved case, whereas a wildcat needs alteration to fit the chamber. So your friend should be able to get some 257 Roberts and fire them in the AI chamber. As noted above, he may want to avoid the possibility that the chamber was cut long and make loads where the case is held back tight against the bolt during firing. In addition to the above seating out of bullets to contact rifling methods, the one that I use is to get 7x57 brass and neck it down to .257", but do so progressively, inserting the case partially into the die, then seeing if it will chamber. At first it won't, so you remove it from the chamber and push it a little farther into the die, then try the chamber again. Keep at it until the cartridge causes slight resistance on turning the bolt handle down. the cartridge will be tight in the chamber so when fired will properly fill out to the improved chamber without stretching the web. the best type die for this is the Wilson type where bushings are used to control the diameter of the neck rather than the type that insert an expander button, then size the neck to smaller diameter, then the button is pulled out, pushing the neck back out to .257". The expander type die will work, but you are over working the brass by each time it is run into and out of the die.

    As for loads, generally speaking, take any tested/published starting load for the 257 Roberts, add 5% and you have a starting load for the 257AI.
     

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