First time Fire Forming to Ackley

Discussion in 'The Basics, Starting Out' started by Greg Duerr, Oct 11, 2012.

  1. Greg Duerr

    Greg Duerr Well-Known Member

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    I have a new .243 AI and I loaded my bullets to jam into the rifleing ..........all went well except two of the cases shoulders were rounded not the sharp Ackley shape. I then noticed when I got home that I needed to use the Redding body die to set the shoulders back as the new fireformed cases were really tight in the chamber.....................once I did that they worked fine. Now Im working up a load.

    Do you have any pointers or sugjections on what happened or what I might do ...............This is all new to me.

    G
     
  2. MTBULLET

    MTBULLET Well-Known Member

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    what load?
    what bullet?
    what brass?
    how much "jam"?

    i normally just load a standard .243 load and shoot to fire form to AI
     

  3. Greg Duerr

    Greg Duerr Well-Known Member

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    Well I was using Nosler Brass, loading with 42gr of RL 19, 85gr sierra, .005 over..............

    I purchased some Lapua brass and will fireform with the heavyer 100gr Speer......................

    Does it help to shoot the heavyer bullet?
    How much Jam do you use?
    Do you resize after fireforming, I have the Redding dies with the Body
    Die and the Miromenter bullet seater.................
     
  4. mm242

    mm242 Member

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    Greg, I'm no expert but with my .280AI the standard cartridge case had about a .004 "crush" fit in the chamber...stiff bolt closure. There was no need to jam the bullet to hold the case rearward because the shoulder of the case held it back. I fireformed with loads just below standard .280 max... after several reloads i haven't had to resize yet. Not sure as to why your fireformed cases are too tight.
    mm
     
  5. FEENIX

    FEENIX Well-Known Member

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    Had similar experience while fireforming to .270AI.
     
  6. J E Custom

    J E Custom Well-Known Member

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    As MM242 Said Most AIs headspace on the neck shoulder junction and not the datum line .

    Depending on how your smith chambered and head spaced, determine how the first firing
    case fit is.

    As stated there should be no reason to use the bullet to head space.

    Rounded shoulder edges are a sign of lower pressure, I would back the bullet off he lands and
    up the powder charge to the middle of the recommended loads.

    Lapua bras is tough and this is not uncommon on the first firing. after fire forming size only
    enough to close the bolt on the round.

    The reason the brass is tight is the brass was not formed well and spring back aloud the case to
    return to a larger size, Or you have the dies set two tight and need to re adjust them.

    Setting up to load/fire form AIs takes time and patients but is well worth the time if done right.

    Depending on the chamber, some dies are just not the correct dimensions for it. (Sometimes a
    neck sizer is nessary to get the best fit in a custom chamber.

    Just some ideas to help.

    J E CUSTOM
     
  7. SSTX

    SSTX Member

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    With my old .257AI, I simply followed Ackley's original recommendation of a "starting" charge of a quick-burning powder, and at least 100gr bullets for fireforming (I used 100gr Ballistic Tips - later 117gr Sierra's - and the starting charge of IMR3031 in the Nosler manual, bullets in contact with the lands). I used Remington brass, and never had a problem fireforming that way, over the course of several hundred rounds. I'm thinking the lighter bullets may have had something to do with your initial results. I bought a separate Redding neck-sizing die, and only full-length resized every third firing.

    SSTX
     
  8. Greg Duerr

    Greg Duerr Well-Known Member

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    Does anyone know what the max case length for the .243 AI is?
     
  9. bronco

    bronco Well-Known Member

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    2.045" is Max Case Length for 243ai.

    Never had a problem fire forming 243ai or 280ai. Was it a rechamber from 243win? If it was did the smith set the barrel back properly (providing proper headspace and a crush fit) or ream it out and screw it back on? You might have a few things working against you.
     
  10. FEENIX

    FEENIX Well-Known Member

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    Here's a .243 Win/.243 AI cartridge comparison ...
     

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