turn necks before fire forming an ackley improved

Discussion in 'Reloading' started by 1sniper, Jul 8, 2011.

  1. 1sniper

    1sniper Well-Known Member

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    I was wondering about the doughnut on the ackley 40 degree shoulder if it would help to skim the necks before fire forming to the 40 degree shoulder?

    Or should I skim the necks after fire forming.


    My barrel is not a tight neck. I just wanted to even out the necks a little.

    Caliber is 22-250 AI

    Thanks in advance
     
  2. Reloader222

    Reloader222 Well-Known Member

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    Donuts would not produce any serious problems where the bullet is seated above the donut. It is only when the bullet is seated past the donut that it could cause pressure problems. I would say that if the bullet does not pass the donut, fireform first and then ream the case.
     

  3. J E Custom

    J E Custom Well-Known Member

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    It is allways a good idea to have good quality brass before fire forming, even if it is a standard
    case the wall thickness difference will move from the outside to the inside causing a misalignment
    of the bullet to the bore.

    Only turn what is nessary to clean it up and make all of the cases uniform/consistant.

    When wildcatting from one caliber to another ,it is also very important.

    Once the case has been fired it cant be trued up as easy, even inside neck reaming is hit
    and miss.

    To avoid the "Donuts" , all you have to do is seat the bullet long enough to hold the case head against the boltface the first time. Note: reduce the loads to a starting load if seating against
    the lands for safety.

    Do it first ! It can only help.

    J E CUSTOM
     
  4. Dano1

    Dano1 Well-Known Member

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    I shoot 3 Ackley improved cartridges. I turn necks for 2 of them. The .30-06AI doesn't need it, However I turn necks on the .243 AI when making my brass from .308 Lake City Match brass and I turn it for the 6.5-06AI because I make it out of .270 Win brass and I have a tight throat chamber.

    The key for turning it prior to fireforming it to not cut into the shoulder too far as to messs up your head spacing.... All Ackley improved design cases headspace off of this point while fireforming, so leaving enough is important as excessive headspacing will mess up the shoulder, cause casehead separations and other problems.....to find this point, turn the necks until the cutter slightly cuts into the shoulder, check the case in the the chamber and makesure it will still chamber with some slight resistance as it is crush fitting and headspacing.

    I then load and fireform and after resizing and cleaning, I check to see if I need to clean up the neck further, as the expanderball seems to push out any doughnut, this takes care of the problem for me.

    hope this helps,

    Dan
     
  5. 1sniper

    1sniper Well-Known Member

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    Thanks for the help.

    I was a little confused because allot of research that I found with google was 50/50 some do it before and some do it after.
     
  6. J E Custom

    J E Custom Well-Known Member

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    Just a little side note on this, It is common sense to correct any dimensional problems before
    firing.

    The chamber is very concentric and when a case has different neck thickness then the
    concentricity if out the window because the inside of the neck is now off by the same error.

    The issue is how much effect it has on the accuracy. The best chance of the best accuracy
    possible will be when everything is Square,concentric and uniform.

    For hunting at close range, It is not an issue unless you want the best accuracy anyway.

    J E CUSTOM
     
  7. 1sniper

    1sniper Well-Known Member

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    Thanks JE so then why do some people do it after fire forming? I was thinking along the same lines as JE but when I read to do it after fire forming, I started to second guess myself.

    I was worried about split necks when fire forming.

    I'm new to neck turning, so I was just making sure before wrecking cases.
     
  8. J E Custom

    J E Custom Well-Known Member

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    If a neck is going to split if is to hard (Needs to be annealed).

    I am not sure why anyone would want to do it after fire forming. Years ago I tried the other
    method of reaming the necks after sizing and found that the reamer wanter to center in
    the neck and did nothing to uniform neck thickness (The main reason for Turning in the
    first place.

    I would have to say if you don't turn the necks to true them before sizing/fire forming, dont
    bother doing it later because the harm is done and improving it is very hard.

    If the brass is very good quality it may not be nessary,but when sizing up or down turning
    the necks before sizing is very important in my opinion.

    J E CUSTOM
     
  9. diriel

    diriel Well-Known Member

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    I have a forster trimmer with the outside neck turn attachment. Works pretty good.

    Gary