30-06 case length???

Discussion in 'Ammunition & Reloading' started by hockeyjr1, Jun 14, 2014.

  1. hockeyjr1

    hockeyjr1 New Member

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    Hey guys I just started reloading 30-06 and came to a road block at max case length..

    Now I know sammi specs are at 3.34" as a max but I got some weird numbers when measuring my gun just now..

    I have a tc dimension rifle, and started with a bullet in the barrel with a pencil holding it against the lands.. Next I took a cleaning rod to the tip of the bullet and made a tape mark.. Then took the bolt and closed it all the way and did the same with the cleaning rod against the bolt face.

    The result number I got was 3.165" as my max case gauge... Now to confirm this I then took a bullet covered in sharpie and slowly step by step seated it deeper untill when I put it into the rifle there was no binding and the black sharpie marks were not touched then took this out and it measured at 3.160"..

    Now what I'm not grasping is how my gun is so far off from max length, and that most of my other 165gr ammo is 3.21" long and never had problems with them..

    Could my gun really be that short? With the space for variance I'm looking at a 3.15 overall length.. This just doesn't sound right to me..

    Has anyone else gotten this low of a number? And should I load to gun length or to factory ammo leggy instead?


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  2. hiwall

    hiwall Well-Known Member

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    Overall length can vary a lot. Actual case case length can not. The max OVERALL length is 3.34" but loading much shorter ones is fine (though in some instances accuracy may suffer).
     

  3. NotMormon

    NotMormon Member

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    What bullet are you trying to load up? Have you checked a factory cartridge with a sharpie to see if it is touching the lands?
     
  4. hockeyjr1

    hockeyjr1 New Member

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    I'm using Sierra 165 gr HPBT, and no I haven't tried with a factory round since the only 165 gr ones I have are hornady and just realized the bullets are way different. Here's a look at them.. ImageUploadedByFirearms Talk1402787797.482726.jpg


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  5. NotMormon

    NotMormon Member

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    That there would make the difference. They have a significantly different ogive not to mention they are HP. If you were loading the same Hornady, you would notice that your OAL would be quite longer than the max using the cleaning rod technique. Go ahead and load em up. You will be fine. My 06 really likes those 165 HPBT's. Been a while since I've loaded any but IIRC, my OAL with those is around 3.20".
     
  6. JonM

    JonM Moderator

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    measuring from the point of the bullet is not a terribly accurate method and basic saami spec is not good enough. you need to use the max coal from the load manual for the specific bullet in question.

    reason being is the widest furthest forward point of the bullet. the bullet maker takes the difference between the ogive and the bullet tip into consideration when listing a max oal.

    to find your rifle's true allowable max oal you need a bullet comparator modified case and calipers.

    trying to determine coal with tape sharpies and measuring sticks is going to cause a kaboom at some point.

    get the proper tools to do it correctly and safely.

    [ame]https://www.youtube.com/watch?v=WCPgKNp8i7o[/ame]
     
  7. NotMormon

    NotMormon Member

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    Yip! The right tool for the job is always the best way to go.:)
     
  8. JonM

    JonM Moderator

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    in this case not using the right tool can kill you or put you in intensive care...
     
  9. hiwall

    hiwall Well-Known Member

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    Ah. Regardless of overall case length a loaded round that does not touch the rifling and is otherwise loaded to spec can hardly blow the rifle up and kill you.
     
  10. NotMormon

    NotMormon Member

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    I'm one of those "unsafe" re-loaders being that I don't use a case length gauge and all the fancy expensive stuff that makes you get .1" groups. There are other methods to determine OAL Edit: and bullet jump Edit: without spending your hard earned cash. However, I do believe that SOME people should use them.

    Loads on the upper end of the scale touching the lands on a 100 degree day COULD end badly.
     
    Last edited: Jun 14, 2014
  11. JonM

    JonM Moderator

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    Bullets seated overly short will increase pressure and possible go into the rifling crooked causing catastrophic failure.

    I seat bullets just under book max coal as measured from the base of the case to tip of given bullet. I've experimented a bit and have cartridge chamber gages but I've found you gain so little from over long seating its not worth messing with. Powder weight condition of the case consistency of the charge and bullet and powder type have far more to do with accuracy than coal does.

    I'm of the opinion that coal has about as much effect on performance as removing a catalytic converter on a car does to its top speed. So many other things have a more substantial effect that its not worth messing with.
     
    Last edited: Jun 15, 2014
  12. hockeyjr1

    hockeyjr1 New Member

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    So I'm still not sure, you guys think I should load to 3.15 like my measurements are telling me? Or to 3.20 like factory loads usually are?


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  13. JonM

    JonM Moderator

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    you should seat them according to book values for the bullet being used. dont measure a factory round and use that data point
     
  14. hiwall

    hiwall Well-Known Member

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    After reloading for about 38 years and loading around two dozen different calibers I admit that I have never measured the overall length of any of my reloads (at least to the best of my fading memory). I can not imagine how many shells I have loaded in that time span but I used to buy my most common bullets by the thousand.
    hockeyjr1 go worry about something else.
     
  15. jigs-n-fixture

    jigs-n-fixture Well-Known Member Lifetime Supporter

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    Load for your rifle. The only time I don't load to match the rifles chamber/throat dimensions is when the magazine length is too short to allow it with the longer bullets, or the length of a lighter bullet doesn't allow enough engagement in the case mouth.

    If you haven't messed up the measurements you could generate higher than normal chamber pressures by loading long enough to put the bullet against the rifling.

    Before you load shorter, be sure to load up some dummy rounds, just to double check. Start by loading the bullets over the factory length, and then backing them down to shorter than you think it is. Blacken the bullets with a felt marker and then try loading them into the chamber and when the bolt closes easily, and the bullets don't come out marked you have found the seating depth. Alternatively you can just spend the $55 for an RCBS micrometer for the 30-06.



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  16. hockeyjr1

    hockeyjr1 New Member

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    After making a few dummy rounds yesterday I came to a conclusion of loading to 3.20.. I drilled and tapped a case and slowly crewed a bolt through pushing the bullet through to the rifling. After 15 times i got an average of 3.205 and since I use a very light crimp I think this will work fine.. I also loaded a long dummy round with the bullet snug but movable and got the same numbers..


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