Question for those who removed expander from FL sizing and use Mandrel

Discussion in 'Reloading Forum (All Calibers)' started by giannid, Apr 14, 2019.

  1. giannid

    giannid

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    So I have a new Seekins SP10 6.5 Creedmoor that I'm doing some load developing. I'm trying to get the most I can long range with this gun. I decided to remove the expander out of the FL die and use a 21st century NT26 turning mandrel arbor after full length sizing to make the ID of the cases more uniform without the hassle of neck turning. I'm having good luck developing a load and have found a few that I like. With my first sizing of new cases I threaded the die all the way in till it touched the shell holder and sized my brass as I didn't know the headspace of fired brass for this rifle. After shooting the brass I checked the size of the brass with the hornady comparator with the 375 bushing and it measured 1.556. So I put that brass through the press with the die screwed all the way in to touch the shell holder so I could back off the die. To my surprise, the brass came out to 1.557 so it actual grew. Tried it a few times and the same result every time. I put the expander ball back in the FL die and with that installed it does push the brass back. I also followed up with the turning mandrel to see if that would push the brass back a bit with no luck.

    So what are you guys doing this to remedy the problem? Is this something I should be concerned with? I've shot rounds that I've sized this way with no problems functioning. For now I'm just using the die screwed in all the way to the shell holder. It just concerns me as you're supposed to push the brass back a bit for sizing and I'm not. Thoughts and opinions would be appreciated as I'm thinking of going back to the expander ball. I am getting good accuracy with the turning mandrel method without the expander installed. Seating bullet pressure has also been very consistent. Thoughts and opinions would be appreciated.
     
  2. LCazador

    LCazador Competitive shooter and reloader for 50 years+ Silver $$ Contributor

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    You do need some bump. I'd grind the shell holder down to give .001"-.002" bump. You really don't need to use the expander each time you reload. It really doesn't accomplish anything but work the brass. Don't be lazy, neck turn if you want the best out of your loads.
     
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  3. SPJ

    SPJ Silver $$ Contributor

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    You measured your case length at the .375 datum and after sizing it grew by .001( a human hair)
    with your Die making full contact at the shell holder.

    You can get punch drunk on numbers and loose your way, (ask me how I know that)
    You also mentioned new brass, not fully fire formed.
    I suggest a Wilson case gage for starters you might not have any problems at all
    you might also try backing off your Die and re trace your steps
    I quit using Dies with expander ball systems
     
    Last edited: Apr 14, 2019
  4. nso123

    nso123 Silver $$ Contributor

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  5. golong

    golong

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    Any time you pull something out of the neck you risk pulling the shoulder forward. I don't use an expander button, ever. If I believe that I need to expand (e.g., case mouth caught the action on the way out) then I use an expander mandrel before I size.

    As far as the 0.001, as mentioned it is nothing. You will likely not even feel it when closing the bolt assuming your chamber is hitting in that exact spot on the shoulder, which it is probably not. Also, the Hornady gauge is okay but at the end of the day it is soft aluminum and not precise. The only real way to measure the shoulder is with something like the L.E. Wilson Case Gage Depth Micrometer.

    Something else to consider is brass does will spring back. The harder it gets, the more spring. If you do not anneal you may want to consider it.
     
  6. DUSTY NOGGIN

    DUSTY NOGGIN

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    the thicker the neck the more you see it

    graphite ??
     
  7. dkhunt14

    dkhunt14

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    What's the difference if you use the expander to make them round and even tension or of the bullet expands them. The brass still gets expanded. I found way better accuracy at 1000 yards using and expander to even out the tensions, even with neck turned brass. Matt
     
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  8. dkhunt14

    dkhunt14

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  9. giannid

    giannid

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    I ended up grinding a little off the bottom of the die to get it to turn down a little. Looks like I'm bumping the shoulders back .002 to .003". I'm using a forster press so changing shell holders is not an option.
     
  10. LCazador

    LCazador Competitive shooter and reloader for 50 years+ Silver $$ Contributor

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    Matt because of brass spring back you'll still have uneven neck tension. Why introduce another variable? I found way better accuracy at 1000 yards not using an expander.
     
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  11. dkhunt14

    dkhunt14

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    According to most the top 1000 yard BR guys they are using mandrels because it gives better accuracy proved by many tests. If you are not turning brass, sizimg pushes the thicker brass farther in, making the inside out of round and off center. Even with turned brass the seating tests prove the seating force gets more even with a Mandrel run in. Matt
     
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  12. Richard Coody

    Richard Coody Gold $$ Contributor

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    First thing i will say is you are.probably oversizing your brass.

    You say it grew a thousandth during the resizing process. would that brass chamber easily after sizing? If so it wasn't fully fireformed. Until a piece of fired brass chambers stiff you brass is not ready to set up a shoulder bump.

    As for removing the expander ball from a full length sizing.die. they made them that way for a reason. It works. The foster full length sizing die expander ball location works best of all. As for pulling.the shoulder out of.place with the.expander ball with proper lubrication i don't see it as a problem. Been reloading over 40 years and i haven't experienced it. A full length resizing die with the expander will in most cases induce less runout than a bushing die.

    Using a mandrel for a.final step in brass sizing is very helpful in adjusting neck tension. Most that use that technique use special mandrels made in 0.005 increments not a neck turning mandrel. I use them myself.
     
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  13. murray brook

    murray brook Silver $$ Contributor

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    Using the bullet to expand your necks can damage the bullet and also induce unwanted bullet run-out.
     
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  14. Webphut

    Webphut

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    Only time I expand my case necks is most often times when I have dropped a case and it dents the mouth of case. I only use an expander mandrel for this. Also on a side note, you do know that molecularly speaking, using an expander bell in a resizing die is not the same as using an expander mandrel. There are two different molecular things happening during the physical process of expanding case necks using either of these methods. Thanks to spring back, expander mandrels work the brass far less than a bell dies. In fact an expander bell works the case neck 2 times more than the expander mandrel does.

    A bell forces the brass to move around it and the collapses back after it has passed through, now it has to repeat the process to remove the bell. With a mandrel, the brass is forced around it. BUT it has to stay put and not only that, the brass needs to find more brass to expand as the cases neck travels further along the mandrel, but it has not sprung back. It molecularly has changed its shape. Kind of like forging. The case is then removed from the mandrel and springs back, but actually less than with a bell, because of the molecular change in the case necks.
     
  15. dkhunt14

    dkhunt14

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    I was referring to using a mandrel to even them out and making .002 tension or having the bullet expand them when seated. Matt
     
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  16. crustyrusty

    crustyrusty Silver $$ Contributor

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    I just found out that redding makes a shell holder kit( a competition kit) that does just this job you need done .. there are 5 identical shell holders on the exterior but where the case head sits that face has been machined in .002'' increments up to .010 total so you just start with the smallest cut first and work your way up till your case fits chamber nicely
     
  17. Ringostar

    Ringostar

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    I believe that the competition shell holders are cut deeper than standard shell holders. So they wouldn’t help in this situation. However with only one firing, I doubt that his brass is even fully formed to his chamber yet.
     
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  18. crustyrusty

    crustyrusty Silver $$ Contributor

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  19. golong

    golong

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    I spoke to Redding today about this very topic as I have 2 new builds that won't bump after the first firing. They said if it does not bump and still chambers then you are in the best possible spot. They also said at some point expect the brass to stretch enough to where it does bump.
     
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  20. perazziguy

    perazziguy

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    +1 for the case gage. With my 22-250 and Forster and Redding dies, just touching the shell holder resulted in extremely difficult chambering. With the gage, alas! Not enough resizing going on. Not anymore, smooth as butter!
     
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