280 Ackley Hart barrel .313" neck

Discussion in 'Reloading' started by woods, Jan 26, 2007.

  1. woods

    woods Well-Known Member

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    280 Ackley Hart barrel .313\" neck

    I just recently got my gun back from Hart after having a new barrel installed. It is a 280AI 40 degree shoulder 26" barrel 1 in 9 twist on a Sako action.

    I bought a box of Nosler 280AI brass. Loaded some 160 and 140 AB's with medium loads of RL22 and IMR4831 respectively. The loaded rounds mic'ed .310" outside neck diameter and chambered easily. All good to go.

    The gun shot well and after depriming the cases I again mic'ed the outside neck diameter of the unsized cases. They measured .311" close to the shoulder and .310" at the end of the neck. A bullet could be forced into the neck by hand with moderate force. Seems like a pretty tight neck. Tighter than advertised. The concentricity gauge showed them to be perfectly concentric.

    No problem, I can outside neck turn the necks down. The brass mic's .013" to .014" neck thickness.

    Question is, how much would you take off the neck and to what thickness.

    I could just seat the bullets, put a light crimp on with the LFCD and shoot again. /ubbthreads/images/graemlins/shocked.gif

    Is some space around the neck necessary?
     
  2. winmagman

    winmagman Well-Known Member

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    Re: 280 Ackley Hart barrel .313\" neck

    [ QUOTE ]
    Is some space around the neck necessary?



    [/ QUOTE ]

    Absolutely, the brass needs to be able to expand to "let the bullet go". I like .003-.005 total in my hunting rifle just to be safe, don't want to run into problems with dirt, dust, or moisture in the chamber preventing the brass from expanding, that could get ugly quick.

    If your once fired brass measures .311 your neck is probably close to the .313 advertised as brass spings back a bit after being fired and cooling down. So all you should need to do is just clean the necks up .001 or .002 and you should be good to go.

    Chris
     

  3. wapiti13

    wapiti13 Well-Known Member

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    Re: 280 Ackley Hart barrel .313\" neck

    .003 should not hurt accuracy & still be safe from jammimg. Since you are hunting, don't go any tighter. Good luck turning down your brass. /ubbthreads/images/graemlins/blush.gif
     
  4. Wild_Bill

    Wild_Bill Well-Known Member

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    Re: 280 Ackley Hart barrel .313\" neck

    as already mentioned your brass will spring back a small amount and because their is only a small amount of cleaence they are coming back close to what they started. If you hunt in dirty and dusty conditions skim the brass 1 thou each side to give some more clearence but if you are happy with it it is safe as is and your necks will last longer the less you have to size them. i only run 1 thou per side on target rifles and i run 2.5 thou each side on hunting rifles where dust or dirt may be an issue. i have seen target rifles jammed up because granules of powder were in the action behind the chamber you must have cleaence so debris can escape.

    Cheers Bill
    Australia
     
  5. Chawlston

    Chawlston Guest

    Re: 280 Ackley Hart barrel .313\" neck

    [ QUOTE ]
    as already mentioned your brass will spring back a small amount and because their is only a small amount of cleaence they are coming back close to what they started. If you hunt in dirty and dusty conditions skim the brass 1 thou each side to give some more clearence but if you are happy with it it is safe as is and your necks will last longer the less you have to size them. i only run 1 thou per side on target rifles and i run 2.5 thou each side on hunting rifles where dust or dirt may be an issue. i have seen target rifles jammed up because granules of powder were in the action behind the chamber you must have cleaence so debris can escape.

    Cheers Bill
    Australia

    [/ QUOTE ]

    I agree, skim .001" off the thickness and then see what you get. I like my brass .011-.012" when I design my reamers. I shoot for .002" clearance on each side of the brass and have never had any problems from dusty to wet climates.

    James

    James
     
  6. woods

    woods Well-Known Member

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    Re: 280 Ackley Hart barrel .313\" neck

    Okay, I neck turned with a Forster hand outside neck turner down to a consistant .013" neck thickness. A loaded round now measures .309".

    Question, will this be the only time I will need to neck turn these cases?

    I also trimmed them all to 3.519" which is .006" less than listed length for the 280AI. I've heard that AI brass doesn't need to be trimmed as much. We shall see.
     
  7. Chawlston

    Chawlston Guest

    Re: 280 Ackley Hart barrel .313\" neck

    [ QUOTE ]
    Okay, I neck turned with a Forster hand outside neck turner down to a consistant .013" neck thickness. A loaded round now measures .309".

    Question, will this be the only time I will need to neck turn these cases?

    I also trimmed them all to 3.519" which is .006" less than listed length for the 280AI. I've heard that AI brass doesn't need to be trimmed as much. We shall see.

    [/ QUOTE ]

    Hello,

    It should be the only time you need to do it.

    James