270 Winchester Ackley Improved

Discussion in 'Long Range Hunting & Shooting' started by ronpet, May 13, 2007.

  1. ronpet

    ronpet New Member

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    Can anyone tell me about the A.I.? There is not a lot of information out there about this wildcat.
    Is there enough of a ballistics improvement over the standard 270 win to warrant the upgrade. How's accuracy?
    Would the 270 WSM be a better choice.
    I sure appreciate any feedback!
     
  2. ol mike

    ol mike Well-Known Member

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    The AI will give you 100-150 fps over the standard cartridge of coarse YOUR mileage will vary.

    The AI will cut the trimming of brass way- way back.
    Berger has some .277 vld bullets coming out at the end of the summer -i'm thinking about a 270 AI myself in the future.
    Should make a nice 6-700 yard pronghorn whitetail cartridge.

    The 270 wsm is a great cartridge also if you plan on shooting farther a bigger powder charge can't hurt.
    Accuracy w/ both will be great providing you have an accurate rifle.
    There is good brass for both cartridges and plenty of great bullets in the .277 size.-Mike
     

  3. LewisH

    LewisH Well-Known Member

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    What about the old .270 Weatherby? It's got more oomph than either the 270 AI or the 270 WSM.

    IMHO the 270 WBY with the Nosler 150gr partition is the best available all around thin-skinned game cartridge.
     
  4. ronpet

    ronpet New Member

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    Thanks for the information.
    The 270 weatherby and the 270 wsm both would require opening up the bolt face to accept a larger cartridge.
    I've got a Sako 270 win standard action and I will probably try the AI which would only require rechambering to achieve almost the same ballistics improvement. Less money and I can use my 270 win cases.
    I would like to know if anyone can point me in the direction of loading data for the 270 Ackley Improved?
     
  5. Freebore

    Freebore Well-Known Member

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    Heres the link form Steve's pages for the 270 Gibbs similar to to the AI, http://stevespages.com/277_7_130.html
    Most improved cartridges can use the max loading for the parent standard case as a good starting point for a particular wildcat. I suggest to start one grain lower than the max standard case loading though to see how a particular powder/bullet respond in your new chamber. If you using older brass with some loading on them I would suggest new brass to fire form or annealing the older stuff as you may split some necks or shoulder areas which will burnish your chamber (not what you really want to happen). Brass is cheap for the .270. You will need a strong load to form the brass correctly. Your 'smith should be able to offer some directions for you to achieve success. FWIW
     
  6. Alan Griffith

    Alan Griffith Well-Known Member

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    Rangemaster,

    I have zero knowledge of the 270 Ackley. What I do bring to the table is personal experience with the 30-06 Ackley. Same concept! From what I gleam, you are keeping the same barrel and just having the chamber opened, so velocity increase from that end will be zip, nada, none. I went from a 22" factory Rem barrel to a 26" SS custom Lilja, along with pushing my pressures, I recongnized a 300 fps increase w/ 180's (2750 to 3050 fps).

    Like you, I wanted to be able to maintain as much of my previous assortment of components and reloading equipment with out having to re-adjust for an entirely different cartridge/caliber combo. I was able to keep the reloading die set up inexpensive by using the wonderful Lee Collet Neck Die. Works great! Though after 3-4 firings, chambering a round becomes difficult due to not setting back the shoulder. Thus my purchase of a Redding custom body die; probably about $70 for you. Call Redding direct for that purchase. I already owned the wondeful Forster Ultra Seater die in 30-06. Forster sent me an Ackley floating chamber which kept me from having to purchase an entire seating die; about $45.

    I did some looking around for propellant charges and ran across a guy who goes by the name of "Ackley Improved User" over on www.accuratereloading.com. He had used an interior ballistic load program (having a senior brain fart at the moment and can't remember the programs name) which when you plug in all the gun/caliber/powder/bullet specifics, gives suggested load data. He then personally tested the load data and discovered a load which was A-typical for the '06 Ackley but worked wonderfully. I too, tried his load of heavily compressed charges of Reloader 25 pushing the Nosler 180 BT or AB and immediately hit upon 3/4 MOA loads at 3050 fps.

    Good luck in you endeavor.
     
  7. ronpet

    ronpet New Member

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    Thanks. A lot of good solid information.
    I feel confident to continue with this project.
    I think it will be accurate enough to accomodate several huting scenarios, including 800-1000 yd. varmits.
     
  8. buk-master

    buk-master Well-Known Member

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    Hello Ronpet I have a question for you I’m trying to build a .270 Win Ack Imp can you give me any feedback on this Wild Cat... Also can you share any load data that you have and what where your velocity’s that where accomplish from this load.
     
  9. Big Jake Duke

    Big Jake Duke Well-Known Member

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    Ronpet-

    Did you ever complete this project and if so, what were the results?
     
  10. budlight

    budlight Well-Known Member

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    I just saw this and I have been a 270AI person for about 20 years. It's a wonderful round because the 270 win case is not big enough to hold the required amount of slower burning powders like IMR 7828. 270 win cases are extremely compressed loads when you put about 60-62 grains of powder in them.

    My AI also has a 29 inch barrel and was throaghted like a Weatherby .250 inches. so were are not exactly comparing apples and apples

    I only really shoot 140's or 150 SPBT for hunting and 115 gr. HPBT's for varmint days. I spent allot of time at the range with the chrono and R-22 and IMR 7828 with LR mag primers work the best.

    I've exceeded 3600 fps with 100 gr. The 115 gr BC is so much better and they can be loaded to near 3450 without case damage

    The weatherby 270 is poor choice. I've done chrono work and load development with a friends gun. You can stuff in about 5 more grains over the AI. But the cost of the cases .......... I did find out that most reloading books are very generous as to listed speeds of reloading data for guns like the Weatherby 270. They just don't do it on the range.
     
  11. BountyHunter

    BountyHunter Writers Guild

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    PO Ackley in his book, Handbook for Shooters and Reloaders Vol 1 states, "as the 270 is already overbore, little improvement can be expected... It is not recommended." Plus he gives no data for it as he considers the standard 270 better, which is another indicator.

    Just because one cartridge being AI'd shows a big improvement, does not correlate into all others especially one already overbore.

    Maybe with the newer powders it can work.

    BH
     
  12. budlight

    budlight Well-Known Member

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    I have that same book "PO Ackley" It was all written with knowledge and data from basically pre 1970. This is before the days of 20 custom barrel makers making longer than 24 inch barrels and slower burning modern powder choices.

    I was just looking through that PO book the other day and he seemed to use very hot powders for the majority of loads and the slowest you see is like IMR 4350 or maybe IMR 4831. That is the stuff I use for my lightest bullets

    Yes, a 270 AI would be over bore for a 22 inch barrel. Poor old Mr Ackley would roll over in his grave at the site of Utra mags or something like my 30-378
     
  13. buk-master

    buk-master Well-Known Member

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    Well I have not completed my project I have a Ruger M77 ultra light SS in 270 win. With a 22 inch barrel I guess that making it Ackley I will have to Re-barreled it and I can’t afford doing that right now. But I will like to have one but dies are very expensive.
     
  14. darndt

    darndt Well-Known Member

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    I will have my 270 ai build back next week. Going start load work with rel 22 and 7828 and 130 and 140 pills