270 Winchester Ackley Improved Load Data

Discussion in 'Long Range Hunting & Shooting' started by buk-master, Nov 30, 2010.

  1. buk-master

    buk-master Well-Known Member

    Messages:
    114
    Joined:
    Oct 25, 2009
    270 Winchester Ackley Improved

    Can anyone Help me on Load Data on the .270 Win Ackley Improve? There is not a lot of information out there about this wildcat. I plan on shooting 110,130, 140,150 Bullet I can’t find any info on this.

    If you have a P.O Ackley Book can you Scan the .270 A.I section for me I will appreciated it.



    buk-master@hotmail.com




    .....................
     
  2. liltank

    liltank Well-Known Member

    Messages:
    4,158
    Joined:
    Nov 3, 2008

  3. tunered

    tunered Member

    Messages:
    12
    Joined:
    Oct 25, 2009
    You can use max loads from the parent case [270win] as starting loads to work from, i think most recomend at least 75% case capacity. ed
     
  4. buk-master

    buk-master Well-Known Member

    Messages:
    114
    Joined:
    Oct 25, 2009
    Thanks you all for the info I have been comparing all Ackley loads with standard loads and it seems that from the max load add 6grains and that will be your max load but of course start with a safe load that will be the max load from a standard load.
     
  5. Big Jake Duke

    Big Jake Duke Well-Known Member

    Messages:
    381
    Joined:
    Jan 11, 2011
    What were your results? I would like to turn my 270 into an improved.
     
  6. Catfish

    Catfish Well-Known Member

    Messages:
    167
    Joined:
    Jan 6, 2007
    Ackley says it is not worth doing there for there is no data for it in his book. I can tell you that the 270 Win. has a case capicity of 4.36 cc and that the improved has a case capicity of 4.4 cc. With a difference of only .04 cc you are talking about an increase in powder charge to equal the same presure would be .1 gr at max. That siad the 270 is a very good round in it`s own right and if you have a custom rifle it`s probly a good shooter, besides that your probly the only one on your block that has one.
     
  7. Big Jake Duke

    Big Jake Duke Well-Known Member

    Messages:
    381
    Joined:
    Jan 11, 2011
    What I can't understand is how badly the 270 improved is trashed, by people who don't own them, and the 280 AI is lauded.

    They should be nearly identical. The 270 win has had a slight edge over the 280 with 140gr. The increase in performance according to some sources by making a 270 improved is 7.8%, the 280's improvement in performance is rated at 7.7%.

    So how can one be a piece of crap and the other the best thing since sliced bread?

    I understand there are heavier bullet choices in the 7mm, but as for shooting Nosler accubonds or ballistic tips, the bullets are too similar to differentiate.

    It seems the people with them love them, and I think I am going to give it a try. IMR 7828 and a few others have breathed new life into the "overbore category", and I think the debate isn't over. So I'll spend a few dollars to make a fool of myself.

    My current load in the 270 win with a 26" Douglas Airguage bbl, runs the 140gr nosler ballistic tip out the barrel at 3200fps with 60 gr of H4831. A hot load, but not rediculous. Use at your own risk. The same load will hold 3012 fps with a 22" barrel. I think the inclusion of a few more grains of powder-in a more effecient burning cartridge AND the 26" barrel will be a really cool long range weapon.
     
  8. budlight

    budlight Well-Known Member

    Messages:
    836
    Joined:
    Sep 30, 2004
    My 270 ai holds @ 6 gr. more powder than a win case 270. RPeter's 270 cases are even lesser volume.

    a 270 win case is very compressed load with 62 grains I mean I long drop tube with small grain IMR 7828 sc clear to the top of the case and smash the bullet in. My ai can take 4 more grains be and below the top.

    The AI has a straighter case and blown out forward shoulders with I think a 40 degree shoulder angle. I had to fire form a couple of cases and send them to RCBS to make custom dies.



    PO Ackleys book kind of sucks. I have it and it is very old school.. You have to consider that it was written about 40 some years ago and they did not have modern slow burning powders and long high quality barrels
     
    Last edited: Jan 14, 2011
  9. archeratlrg

    archeratlrg Member

    Messages:
    17
    Joined:
    Jan 30, 2012
    Wanted to add my 2 cents in here. With the loads you've quoted, you won't get enough difference by "improving" your case to make it worthwhile. I've built and shot a lot of wildcats over the years and some are great, others will actually perform no better and in some cases worse than the parent cartridge. You mentioned the 280 improved as a case in point, but with it, you only bump up your velocity 50 to 75fps with 150gr, bullets...in my opinion not worth the extra powder or cost to rechamber. Can you get higher velocity improving your 270? Yes...but, you will be way over safe pressure limits if you do so, so tread cautiously. I've seen too many rifles blown up to recommend a green light for you on this. Good luck
     
  10. budlight

    budlight Well-Known Member

    Messages:
    836
    Joined:
    Sep 30, 2004
    I guess you don't understand reloading, powder burn rates, and case size effect on pressure. You could say run 60k pressure in a 30-06, a 300 win mag, 300 Ultra mag, 30-378 Weatherby One case has a max of 60 grains and the biggest 120 grains of powder. The peak pressure is the same the difference is slow burning powder can give a higher average pressure for the full length of the barrel. Even make use of longer barrels

    I will agree that very little is gained with additional powder in short barrel rifles. That is why my barrels are at least 28 -34 inches long

    I personally have never seen a blown up gun.
     
  11. FEENIX

    FEENIX Well-Known Member

    Messages:
    9,806
    Joined:
    Dec 20, 2008
    L:DL! That's OK, I like it when people thrashes the idea of transitioning to .270AI because I am in the process of acquiring parts for a .270 AI build. Cheers! gun)
     
  12. Long Time Reader

    Long Time Reader Active Member

    Messages:
    33
    Joined:
    Jul 10, 2013

    He wasn't thrashing the 270AI - He was thrashing people that say the 280 AI is good and the 270 AI bad.
     
  13. FEENIX

    FEENIX Well-Known Member

    Messages:
    9,806
    Joined:
    Dec 20, 2008
    That's what I said ...
     
  14. CogburnR

    CogburnR Well-Known Member

    Messages:
    555
    Joined:
    Dec 18, 2010
    I have a 270 Sherman which is a blown out, lengthened and improved 270win. It holds about 10% more powder than a regular 270. I currently use 64gof RL22 with a 130g Berger which is 10% over the max listed for RL22.

    If I understand correctly a 270 AI has about 5-7% more capacity than the 270 Win and would likely have powder charges around that much heavier than the 270WIN.So you could work up loads up to 7% over book loads for the 270 and be in the ballpark(start that much lower also and work up).