Case length and OACL

Discussion in 'The Ammo & Reloading Forum' started by Herman, May 6, 2012.

  1. Herman

    Herman New Member

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    When reloading for my 30-06 with the case trimmed to the proper length and the OACL correct the center of the "channelure" is .075 above the end of the case and a 110gr bullet sets right on top of the case. What is the deal???? The round works fine through the action of my Browning Abolt> how about some comments?
  2. 76Highboy

    76Highboy Well-Known Member Supporting Member

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    What is the C.O.L. for your particular bullet? Is your cartridge the C.O.L. after you have seated the bullet?
  3. The_Rifleman

    The_Rifleman New Member

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    The post reads as if you think there is only one Case Overall Length for a 30-06. Each bullet has its own specific seating depth; whereas it will possibly have a different COL.

    I don't go by a measurement, I go by where the bullet's cannelure rests in the case mouth, then I measure for reference in my reloading data.

    [​IMG]

    I'll seat them like the top one, (30-06,) then measure. If the next batch of bullets are a bit off like the 30-30 case on the bottom, I'll leave it alone. But if it further off than that I'll seat it like the top and call it good.

    (I load the 30-30 cartridges singly, directly into the chamber; when using pointy bullets.)
    Last edited: May 7, 2012
  4. steve4102

    steve4102 Former Guest

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    What do you mean that your OAL is correct? Numbers and bullets would help.

    Are you using the SAAMI max of 3.340? If so, don't, that number means little to nothing for the handloader.

    This is from Weatern Powders Load data.

    SPECIAL NOTE ON CARTRIDGE OVERALL LENGTH “COL”
    It is important to note that the SAAMI “COL” values are for the firearms and ammunition manufacturers industry and must be seen as a
    guideline only.

    The individual reloader is free to adjust this dimension to suit their particular firearm-component-weapon combination.
    This parameter is determined by various dimensions such as 1) magazine length (space), 2) freebore-lead dimensions of the barrel, 3)
    ogive or profile of the projectile and 4) position of cannelure or crimp groove.



    Go here to learn how to set up your seating dies for YOUR rifles OAL.

    http://www.thefirearmsforum.com/showthread.php?t=97328
    Last edited: May 7, 2012
  5. Herman

    Herman New Member

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    The dimensions I am referring to are those given in the Hornady reloading manuel, 7th edition. My OACL is the same as C.O.L. and I understand that it is actually different for many cases.
    I understand the relationship of the base of the bolt to the chamber depth and I thought it "could be" hurting my accuracy to seat the bullet .075 deeper into the case, to accomodate the canelure, thus moving it at least that much further from the rifleing lands.
    Is it common for the COL stated in the reloading manuels to create such a difference in the distance from the mouth of the case to the center of the canelure?
  6. LDBennett

    LDBennett Well-Known Member

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    Herman:

    Since you have not given us all the details I have to assume them. Hornady, in my search, makes no 110 grain 308 caliber bullet with a canneler so you must be using someone else's bullet and Hornady reloading data (which is usually OK). The 110 grain bullet, while OK to use in 30-06, is probably for some other cartridge with different dimensions (??). I suggest you use the reloading data from the bullet manufacturer, at least for the seating depth.

    And... Bolt guns do not have to have a crimp. Usually neck tension is all that is required.

    If you go to the LEE Factory Crimp Die and only seat the bullets using the provided seating/crimp die then you can have almost any seating depth you need because the LEE FCD does not need a cannelure for a crimp.

    While there is reloading data for the 110 grain (and even 100 grain) bullets, they are a long way from the center of the usable bullet weights for 30-06. The 110 grain bullets are often used in different cartridges and drafted for use in the 30-06. You would be better off with a little heavier bullet made for 30-06 or get a real varmint cartridge like 223, 243, or one of the many others. But that is my opinion. As long as you reload inside the parameters in reloading manuals you should be OK but do use the bullet manufacturer's cartridge OAL at a minimum. If such data does not exist then change bullets.

    LDBennett
  7. steve4102

    steve4102 Former Guest

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    Please give details of bullets used as well as your COAL.
    Thanks
  8. 312shooter

    312shooter Active Member

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    If I am understanding your description, the cannelure exceeds the case mouth, so if the bullet where seated deeper everything would be correct. Well, seat the bullet so the cannelure is within the case mouth, make sure the OAL is not below minimum length and go have fun. LD has a good point, forget crimping if your shooting a bolt gun.
  9. Bindernut

    Bindernut Well-Known Member

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    LD and Steve are both spot on the money.
    More details are needed on the bullet that you are using.
    Is it a Spire Point, Round Nose, etc and what brand is it?

    Typically, the listed COAL (Cartridge OverAll Length) measurement is a a general guideline, as Rifleman mentioned. That COAL will sometimes coincide with cannelure location but most of the times it won't.
    If you need to use the cannelure for crimping, then seat the bullet to that depth and crimp as needed. Otherwise, where the cannelure is located in relation to the case mouth can be ignored.

    As LD noted, Hornady doesn't make a 110gr with a cannelure and a 110gr of any style is gong to be very short in any .30-06 chamber. Any style of 100/110gr will have a considerable amount of freebore (bullet jump before entering the rifling) since most .30-06 chambers have enough throat to accept the big long 220gr round nose bullets without them contacting the rifling.

    Also, a 100/110gr is a very short bullet and doesn't intrude into the case very much at all so the extra 0.075" seating depth that you would need to seat to the cannelure isn't an issue in this particular situation. It may be an issue with longer bullets or with certain powder/load combinations that fill the case to at or near the 100% load density point.

    Again, please post up a little more info and we can help you out with more specific answers.
    And Welcome to TFF!
  10. mikld

    mikld Active Member

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    Unless you are crimping the cartridge, disregard the cannalure and load to OAL listed for the specific bullet used...
    Last edited: May 8, 2012
  11. Herman

    Herman New Member

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    I am loading a Hornady 165gr BTSP. The refference to the 110 gr bullet was jus that, a refference to show that if if tried to load it at the Stated COL it would simply set atop the case.
    FRom Hornady reloading manuel edition 7 page 471.
    case length 2.494
    Maximum COL 3.340

    From my measurements the Hornady 110gr SP is 0.825. Add that to the 2.494 and get 3.319 or .021 would be inside the case neck.

    AGain the 110gr bullet was just to show what would happen if loaded to the Max COL. So back to my original question, am I loosing accuracy(in my bolt action) by moving the bullet back to the canelure or should I load to the Max COL for max accuracy since at MaxCOL my bullet is not touching the lands???? Is there other ifo that is needed.
  12. The_Rifleman

    The_Rifleman New Member

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    Like I said in my original comment.
    The pic I provided is displaying the exact bullet you list, it is in a 30-06 case at the seating depth the 7th Edition Hornady loading manual prescribes for that bullet; 3.230, fits perfectly, shoots wonderfully!

    Where are you getting these notions? I get less than half inch groups seated in the cannelure, just as in the pic I have displayed.

    There is no magical property of "Max COL" as far as accuracy. Not exceeding the "Maximum COL" is to assure magazine operation.

    Check this out:
    [​IMG]
    That is a COL of 3.468! Will not work in a magazine, but the accuracy is wonderful in my M-1917.
  13. steve4102

    steve4102 Former Guest

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    Herman, we are here to help, so let me see if I can clarify a few things for you.

    First the Max COL listed in the manual is a SAAMI spec and it is for ammunition manufactures only. It is their specs so each and every round manufactured and sold will fit into the chamber of each and every rifle sold. It has absolutely nothing to do with handloading. Ignore that COL.

    This is from Western powders load data.

    SPECIAL NOTE ON CARTRIDGE OVERALL LENGTH “COL”
    It is important to note that the SAAMI “COL” values are for the firearms and ammunition manufacturers industry and must be seen as a
    guideline only.
    The individual reloader is free to adjust this dimension to suit their particular firearm-component-weapon combination.
    This parameter is determined by various dimensions such as 1) magazine length (space), 2) freebore-lead dimensions of the barrel, 3)
    ogive or profile of the projectile and 4) position of cannelure or crimp groove.


    You have Hornady #7, yes. Go to page 63 and read what it says about seating depth. It will tell you that the handloader has complete control similar to what Western powders says above.

    That is one of the advantages of handloading, we can make em long or we can make em short, it is entirely up to us.

    One of the "rules of thumb" as far as seating depth is to seat the bullet at least one bullet diameter into the case neck. For you and this cartridge that would be at least .308 into the neck.



    Go to page 472 for a list (stated) OAL that Hornady used to gather their data for 110gr bullets.

    For a beginner reloader it's best to seat your bullets according to the load data you have. In your case that would be page 472 and 475 and forget you ever read 471 and 3.340.
  14. Herman

    Herman New Member

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    Thanks for the "help." I guess I have just been reading a little too much. Its not like I just started loading yesterday, mater of fact it was in the early sixties when I got out of the service, that I started. I loaded, primarily for hunting and when I started it was for a Rem. 742, 30-06 and I started out full length resizing and have done that for all of the 6 calibers that I now load. I have killed over a hundred Whitetails and close to a dozen Elk with my reloads. In the past I set up my seating dies to match a factory load and never paid a whole lot of attention to anything except powder measurement. But in several publications I have seen statements such as the following from the 7th edition of the Hornady manuel all the way back to a Spear and a Hornady of the 60s that sounds to me like getting the bullet out closer to the lands spells accuracy. Don't know but thanks anyhow.
    Oh well, crap, I gotta learn to down load pictures on this site. But I am sure you know what I mean.
  15. JohnTheCalifornian

    JohnTheCalifornian Member

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    I too have seen it mentioned several times, even from members here who load thier bullets close to or just touching the lands. You can even buy fancy gauges from Hornady that you can measure your chamber to so you can get your bullets right on the knats booty.
    Loading like that is not a guarantee that you will see greater accuracy, as it is with any other method used to achieve greater accuracy. It's just a matter or testing at different lengths, powders, charges, primer, etc. that will hopefully get you better accuracy. And like others have posted, they are loading to the cannelure and have great results. So, theres proof right there that you can achieve great accuracy loading at the lands, or just off of them, or not even close to them.


    (Boy, I sure used the word "accuracy" a lot in that post......:dontknow:)
    Last edited: May 8, 2012
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