the dredid doughnut

Discussion in 'Reloading' started by rdr59, Jul 16, 2017.

  1. rdr59

    rdr59 Member

    Messages:
    9
    Joined:
    Jun 8, 2016
    I have a question about the doughnut. I recently got a bushing die. While trying different bushing i had one that would let the bullet slide in then it would hit at the bottom of the neck.I take it this is the doughnut. I don' seat my bullets that deep so it doesn't interfere with seating. So will it cause me any problems.
     
  2. Barrelnut

    Barrelnut Well-Known Member

    Messages:
    2,376
    Joined:
    Dec 16, 2013
    Yep, that's the donut. I have gotten them when resizing brass, fired in a long chamber, back to minimum SAAMI specs. Which basically means I bumped the shoulder waaay back. I have not found it to bother anything as long as the bullet does not need to be seated too deep in the case.
     

  3. blinderthanascope

    blinderthanascope Well-Known Member

    Messages:
    107
    Joined:
    Jun 25, 2015
    nope
     
  4. Dgd6mm

    Dgd6mm Well-Known Member

    Messages:
    1,186
    Joined:
    Jul 14, 2008

    You are correct. If you do not seat your bullet to where it is in the donut area you will be fine.
     
  5. Trickymissfit

    Trickymissfit Well-Known Member

    Messages:
    4,071
    Joined:
    Jun 11, 2010
    kind of a common issue with high degree shoulder angles (think Ackley 40 degree shoulders). The K&M toll reams the doughnut out, but trust me it'll be back. That's why I prefer the 30 degree shoulder best of all.
    gary
     
    Barrelnut likes this.
  6. newmexkid

    newmexkid Well-Known Member

    Messages:
    591
    Joined:
    Apr 11, 2011
    I encountered the dreaded donut when I got on my recent 'wildcat' build(s). Thought I was doomed. Rest assured they are no problem if you don't seat the bullet too deep.
     
    blinderthanascope likes this.
  7. gte901m

    gte901m Well-Known Member

    Messages:
    71
    Joined:
    May 18, 2014
    As others have mentioned, its not a problem if the bullet is not seated into the donut.

    However, you will have a problem if you ever decide to full length size and pull an expander through (everyone just gasped...a full length die with an expander)

    I have found through testing that donuts are one of the primary contributors to concentricity issues with full length sizing with an expander. I have been able to maintain <0.003" bullet concentricity while full length sizing if I inside neck ream with a Wilson neck reamer after firing. I speculate the thickness of donuts are not symmetrical, which encourages the expander to pull off center.

    From using pin gauges to measure fired brass necks, I have found that donuts form in almost all the bottleneck cartridges I load when neck sizing.

    I'm not advocating FL sizing with an expander, but thought I would mention it in the event you need to push the shoulder back after repeated firings and all you had was a FL die. A redding body die compliments neck sizing well.
     
  8. dok7mm

    dok7mm Well-Known Member

    Messages:
    471
    Joined:
    Apr 13, 2015
    It will happen and the posts above explain it pretty well. As said, if you don't seat past that point, then no problem.

    I have avoided this problem by using an expander mandrel to set my my final neck I.D. I also neck turn my brass, going slightly into shoulder. If the donut reappears, I will expand again and return the neck into the shoulder again. By then, I will usually not be seating the boat tail/bearing junction into the donut area.
     
    jfseaman likes this.
  9. rdr59

    rdr59 Member

    Messages:
    9
    Joined:
    Jun 8, 2016
    thanks for all your input. This is a 280 AI and i didn't think about the expander but thats why i decided to use a bushing die so i didn't have to use it. thanks again for all your help.
     
  10. dok7mm

    dok7mm Well-Known Member

    Messages:
    471
    Joined:
    Apr 13, 2015
    Just so there is no confusion, I am referring to a expander mandrel, not the button on a FL die. It is a tapered mandrel situated in a holder that screws into your press. I use the K&M setup, but Sinclair and PMA Tool also makes them.

    The mandrel forces imperfections inside your neck to the outside, similar to an expander ball, but with less chance of pulling your neck out of alignment.

    A bushing die forces those imperfections to the inside of the portion of your neck compressed by the bushing. That's why many use the mandrel to uniform neck interference or tension, normally .001-.003" under bullet diameter, I use .002" normally. If you are reducing neck diameter more than .004" , from fired, you may have quite a variance in actual neck tension, depending on your brass quality.

    I'm getting off your original question. You have no problem unless you want to seat deeper or go to a longer bullet. I just wanted to answer your reply.
     
    jfseaman likes this.
  11. jfseaman

    jfseaman Well-Known Member

    Messages:
    3,583
    Joined:
    Apr 8, 2012
    What dok7mm said!

    I now use mandrel to set final neck ID.

    I use an oversize mandrel (.002 over bullet) to set a smooth ID, then neck turn. No more donut even when I need to FL size.

    BTW, FL sizing I use an undersize "expander" if needed to decap. Usually just remove the entire rod. Decap using a Lee decapper.