help! seated bullet runout!

Discussion in 'Reloading' started by Frogman77, Jul 3, 2010.

  1. Frogman77

    Frogman77 Well-Known Member

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    Hey guys, I also posted over on snipershide, but I wanted to get some of your expertise as well.

    I've been trying to figure out where my bullet run out is coming from. I tested my fully prepped necks and most of them I can get to no more than .001" TIR on the necks.

    I'm using a redding comp seater, and after seating my bullet runout varies from .001 to as much as .007" TIR.

    case prep as follows:

    lapua brass, skim neck turned to neck thickness of .014-.0145"

    hornady 208 amax

    rcbs JR3 single stage press

    redding shellholder held in place with rubber o ring

    redding body die

    Trim and chamfer on wilson trimmer and with vld tool

    clean ID of necks with steel wool on bronze brush after tumble

    redding comp neck bushing die (I also tried with a lee collet die and the neck runouts were higher, up to .002" TIR so I stuck it out with the redding bushing die)

    redding comp seater, seat then rotate case 1/2 turn, then complete seating


    a few things to note is that in using my wilson case trimmer I need to rotate the case holder to get the cut all the way around the case mouth. I basically rotate the case holder until there's no more cutting by the blades. Also, my vld trimmer in the wilson trimmer has been cutting unevenly, I have a k&M vld tool on order.

    I've tried floating my dies and not locking down the locking ring but still to no avail. All my cases after seating measure .001" TIR or less on the necks but the bullets still measure anywhere from .002 to .007 TIR with the majority being in the .004-.006 zone.

    Any thoughts would be great.

    I also have a forster co-ax coming in the mail hoping that will help as well.

    Thanks in advance.
     
  2. Strider

    Strider Active Member

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    I have had the same issues with secant ogive bullets in my 7mm STW. I'm using the Redding Comp. seating die, I found that if I set the bullet in the case as close to perfect as possible, run it up until I feel the spring in the die just start to compress, then pull ithe case and started bullet out and check and adjust runout (firm sidepressure with a couple fingers will easily do the job if you don't get the bullet seated very far), and then complete seating with a few rotations of the case on the way up, that gets about 2/3rds of the rounds to 0.001" runout or less. With all the trouble this process is and a 65% "success" rate, it isn't a perfect soution but it is a significant improvement for me.

    Since I have the same issue, I will sit tight and hope someone tells us a better way. One suspicion I have is that the seating die is desiged for a tangent ogive and the tip on the secant ogive if bottoming out in the die. At least my issue is with the VLD's.
     

  3. Frogman77

    Frogman77 Well-Known Member

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    redding makes a vld seating stem. give them a call they will point you in the right direction.. Check your seat stem, if it doesn't fit your bullet right, you need the new seat stem...

    I thought that was my issue, but my seat stem fits the amax bullet fine.

    I will try your suggestion though..
     
  4. trueblue

    trueblue Well-Known Member

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    I think you will enjoy your Forester press. It is all I have ever used. I personally have never checked runout, so take this for what it is worth.
    -With VLD bullets, you may need to get a stem that is made for them for your dies.
    -When seating a bullet, I seat the bullet, then turn it 180 degrees and seat it again. Don't no if it helps, but I have reloaded some pretty accurate ammo.
    -I would do all neck chamfering and trimming and then reisize again to see if it helps.
    -Also, try not to use the plunger button when you can

    A discription of you reloading process might help find the problem. Are you running heavy neck tension, do you feel a difference in seating pressure on some cases than others, how far are you bumping the shoulder, ect ?
     
    Last edited: Jul 4, 2010
  5. woods

    woods Well-Known Member

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    What bushing size?
     
  6. Frogman77

    Frogman77 Well-Known Member

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    Here's my process:

    new virgin lapua brass

    I don't trim them at first because they're already right at about 2.487" within .001"

    expand with sinclair mandrel

    neck turn with forster turner to .014"-.0145"

    size in redding body die.

    Redding bushing die .336" bushing for a final od neck of .335"

    Redding comp seater with vld seater stem

    208 hornady amax. (neck tension should be right around .001" Bullets don't budge at all even with firm pressure on the table.

    (After firing 4 times I anneal the necks)

    After firing:

    tumble wipe clean

    clean inside of necks with steel wool

    bump shoulders back .001-.002"

    Size neck down with bushing die (Fired cases measure .339 to .3395" on the necks. Using the .336" bushing gets me right at .335" for a final neck od. Loaded neck OD is .336")

    Trim and chamfer on the wilson trimmer (again, issue with un even chamfer on the wilson vld tool may or may not be a culprit here.)

    BAck to the tumbler to remove remaining case lube.

    After wards I run it back through the neck sizer for good measure, make sure nothing got dinged around in the tumbler.

    Total runout on the case necks after all prep is no more than .001"

    Charge then seat bullet half way rotate 180 degrees and finish seating.

    I've tried floating the seating die and not locking down the lock ring and I also use a rubber o ring around my shellholder instead of the retainer pin to help the case self align.

    results are still the same. .002-.007" TIR measured about 1/8" from the tip.

    All the lapua brass that I measure for neck thickness variance out of 70 cases only 12 measured .0015" in neck thickness variance. All the rest were .001" or less.

    Unless this first batch of 30 cases I loaded up had more cases in it with .002" or more of neck thickness variance to begin with??? Doesn't seem likely with lapua brass, and even so, would .002" of neck thickness variance cause up to .007" of TIR on a loaded round???

    Thanks for the input guys. Let me know what you think about my loading procedure and if there's something I might be over looking.
     
  7. woods

    woods Well-Known Member

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    With a OD of .335" and neck thickness of .0145" then the math would be:

    .335"-.0145"-.0145"=.304"

    for a bullet grip of .004"

    That is a little strong. Perhaps if you used a .338" bushing for an OD of .337" (after springback) then you would get a bullet grip (or neck tension) of .002" and that might make a difference. A set of pin gauges
    [​IMG]

    might give you a surprise on how the actual dimensions of the ID of the neck. It has surprised me sometimes.
     
  8. TOM H

    TOM H Well-Known Member

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    One thing I'll do after using a bushing die is use an expander mandrel might give you the right amount of spring back to hold the bullet. Since I have afew tight neck rifles and I like to clean up the necks on some calibers they sure can help and I have some from Sinclair,K&M also acouple from Hart.

    Here a good article from 6mmbr afew years ago about using them.

    Neck-Expander Mandrels for More Uniform Neck Tension AccurateShooter.com Bulletin
     
  9. Frogman77

    Frogman77 Well-Known Member

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    woods,

    .335- .0145-.0145= .306 at least that's what I get with the math unless I'm doing something wrong??

    Tom, I use a sinclair expanding mandrel before neck turning, but are you saying to use it after I neck size with the bushing die???
     
  10. woods

    woods Well-Known Member

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    You're right, no wonder I flunked math!
     
  11. Frogman77

    Frogman77 Well-Known Member

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    I think I might have figured something out, although it's still problematic.

    I took a known case to have low runout, seated a bullet 5 times and consistently got a seated round TIR of .001 or less.

    So I think my sizing and seating process is sound.

    then I annealed the case to see what would happen.

    after annealing, my sized neck TIR still remained .001"

    but after seating my TIR on the loaded round measured .0025-.003"

    I'm using 650 deg F tempil stick about 1/4" below the shoulder and a propane torch. Rotating the case in a drill until I see the tempil stik just change.

    Why would annealing cause increased runout??? Could it be because I annealed when it wasn't necessary? Would that change the characteristics of the brass that much??

    Any Thoughts??
     
    Last edited: Jul 4, 2010
  12. RDM416

    RDM416 Well-Known Member

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    Frogman77,

    One thing I have found to help runout is when I am seating bullets I will bring the ram down and just lightly bump the bullet, raise it slightly and rotate the case with my finger. I will do this several times with just a little more pressure each time slowly starting the bullet, then go ahead and seat it in two or three more stroke/rotate of the press.

    This sounds a little time consuming but it is really is not as you can raise the ram slightly with one hand and use a finger of the other hand to spin the bottom of the brass. I don't try to be precise with 1/4 or 1/2 turn increments..... I just use a finger and spin it a little.

    When I use this method I can generally keep runout measured at the very tip of 300 SMK in a 338 Khan (which makes for a very long round) at .001 to .002 with most under the .001 mark. Using the exact same setup and just gently seating the bullets with one stroke my runout will go up to .005 to .006 with no other changes. Try it, you may be surprised.

    If your sized cases are not true by .001 or more, you can use the same partial stroke and rotate method and it will true up your cases.

    For you doubters out there...... and to give credit where credit is due, this is a tip Kirby Allen suggested to me several years ago when I was dealing with runout issues......

    I also use a Forster press for sizing, but I have to use my RCBS for seating as my comp type seating die is too tall to clear the fork in the handle of the Forster.
     
  13. Frogman77

    Frogman77 Well-Known Member

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    any thoughts to why my runout increased after annealing?? Am i doing it wrong??
     
  14. Buffalobob

    Buffalobob Writers Guild

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    YES.

    Anneal your cases after they are fired and before sizing.