bullet run-out

Discussion in 'The Basics, Starting Out' started by trb0, Aug 5, 2005.

  1. trb0

    trb0 Well-Known Member

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    I'm loading 139 grain lapua's for my 6.5/284 and was wondering what was the norm for bullet runout.
     
  2. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Timbo,

    If you have run outs in the 0.0015" range or less you have match grade ammo as far as bullet run out is concerned.

    0.002" is acceptible in most cases but anything in teh 0.003" and higher is getting pretty off for long to extreme range performance.

    It will greatly depend on what dies you are using to load your ammo.

    Good Shooting!!

    Kirby Allen(50)
     

  3. trb0

    trb0 Well-Known Member

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    I was using rcbs dies and was getting .008 runout so I switched to Wilson seater dies but still get .0045 to .005 runout on the finished cartridge, with less than .001 runout on my cases. any suggestions? thanks timbo
     
  4. Varmint Hunter

    Varmint Hunter Well-Known Member

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    My guess is that your neck run-out is being introduced by the sizing die or sizing operation. Check the neck run-out on fired cases and then again after every step of your reloading process. This will tell you where the problems originates.

    Once you determine what is causing the problem, fixing it will be easier.
     
  5. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Timbo,

    Are all your necks trimmed to length. And also trimmed perfectly square? Are they all chamfered as squarely as possible. If a case neck is uneven or the chamfer inside the case mouth is uneven, it will induce a cant in the bullet as it is seated.

    Neck thickness variation can also effect run outs if the variation is large enough.

    Kirby Allen(50)
     
  6. daveosok

    daveosok Guest

    Hey Kirby

    What do you think of the bullet straighteners I've seen on a site somewhere?
    They sorta look like a die but have a screw from the side that "pushes" the bullet back to center some have indicators to measure how much its moved some dont.
     
  7. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Daveosok,

    I have heard decent report on them but I have also heard they can be time consuming. TO be honest, using a set of top end dies generally results in no need for these but to answer your question, I have heard good reports but have not actually tested on myself.

    I have been thinking about getting one for the 50 BMG but have been to busy to really get the 50 out and play with.

    Later,

    Kirby Allen(50)
     
  8. D.P.

    D.P. Well-Known Member

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    [ QUOTE ]
    My guess is that your neck run-out is being introduced by the sizing die or sizing operation. Check the neck run-out on fired cases and then again after every step of your reloading process. This will tell you where the problems originates.

    Once you determine what is causing the problem, fixing it will be easier.

    [/ QUOTE ]

    I would go through these steps and also measure the neck of the fired case, sized case, and sized case with a seated bullet. Over sizing caused me the same problem. I light size the body to set the shoulder then do the neck with a bushing just enough to get the tension I want.
     
  9. kraky2

    kraky2 Well-Known Member

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    Have any of you guys ever tinkered with the Lyman "m" die? There are some guys on another forum that do alot of shooting and swear by it. It has a slight swell at the top of the mandrel to ever so slightly bell the case mouth. It's more designed for seating lead bullets. But what's being found is it makes bullet seating more accurate....I suppose for the reasons above--it takes away the factors of square trimming and chamfering. Some people arent even doing inside chamfering--they just do an ever so slight crimp when done. I bought a couple of these dies cause they are cheap (about $12) and they work really well for ironing out new case necks......but I think they have a calling for more than that. They also help when using coated bullets like xlc's and winchester ball tips.
     
  10. trb0

    trb0 Well-Known Member

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    I squared and trimmed all of my brass and cut my runout to about .0025 to .003. thanks guys. timbo
     
  11. Delta Hunter

    Delta Hunter Well-Known Member

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    Try a Lee collet neck die. It pretty much eliminated all of my runout problems.