fire form brass question

Discussion in 'Reloading' started by timmyatnop, Jul 3, 2012.

  1. timmyatnop

    timmyatnop Well-Known Member

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    Has anyone here, ever fire formed 243 brass to 6mm cm cailber. If so have u ever got a donut around the inside of the neck, and if so what is the best way to remove it?
     
  2. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    Not that conversion, but I've fireformed plenty of rounds. Usually if you don't get complete fill, you are a bit light on the fireform load. I asume that's what you mean for donut. Simply fire it again with a full pressure load if it's only a small fill issue, and if it's a bigger issue, you need to step your fireforming load a bit.

    Reading your other post it seems you also have a thickness issue. You may have to remove metal by turning or reaming the necks then; I've never had a thickness issue and I've done hundreds of rounds to other calibers.
     
    Last edited: Jul 3, 2012

  3. backwoods83

    backwoods83 Well-Known Member

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    Use a 6mm inside neck reamer to remove the donuts, its actually pretty common. Watch out about my replies though, some seem to think I don't know my a$$ from my elbow. Good luck.
     
  4. TOM H

    TOM H Well-Known Member

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    Here something interesting

    .243 variants: how to stretch barrel life? -
     
  5. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    You got a chuckle out of me on that one.

    Most of the forming I've done has been on la belted cartridges, so I haven't worked with quicker tapering rounds very much. I'm kind of surprised there isn't a brass that's close that doesn't have thickness issues when you fireform. About the biggest thing I've seen with belted cases is some win brass gets a bit thin in the neck and neck tension suffers if you are using regular dies.
     
  6. timmyatnop

    timmyatnop Well-Known Member

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    I dont have the gun or the brass yet, mabey iam getting the cart before the horse, ive just been reading about donuts when fireforming, hope i dont have that problim but who knows, thank u guys for the replies and the link to 6the mm br forum good stuff.
     
  7. backwoods83

    backwoods83 Well-Known Member

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    Most of the time in your case Timmy, is that you will get donuts at the neck shoulder junction when for instance you neck brass up or down and then form them into a different caliber with a 40 degree shoulder and the brass flows toward the neck, nothing a reamer can't fix. In your case you're just pushing the shoulder back on the 243 case and blowing it out to 30 degrees, you shouldn't have any problems.
     
  8. timmyatnop

    timmyatnop Well-Known Member

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    Awsime that sounds great, i cant wait to get it and start shooting. Thanks for all the advice.
     
  9. TracySes23

    TracySes23 Well-Known Member

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    .243 is a 6mm caliber. They both use the same bullet diameter. If your reforming 243 Winchester to an improved version, then you've already seen what you need to know.

    Spencer
     
  10. Mikecr

    Mikecr Well-Known Member

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    I can't pull up drawings right now, but if he's pushing the shoulder back with a die, he'll have a donut because brass in the shoulder becomes a thicker part of the new necks.