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Thread: Bullet seating depth .308

  1. #1

    Bullet seating depth .308

    Hi all
    I am reloading .308 with hogdons 4895 and hornady 150 grain sst bullets the lee reloading manual that I am using states a minimum length of round as 2.800
    when I seat the bullet at this depth it is not any were near the crimp mark on the bullet is this correct or could I seat the bullet deeper ?
    I am quite new to reloading particularly .308 any advice would be welcome

  2. #2
    Im using 43gr of varget, 2.75ins col, federal primers, lapua brass

  3. #3
    What make rifle is it?

  4. #4
    I thought the MAXIMUM length for 308W was 2.800 or maybe 2.810 though I guess in many rifles this will be limited by magazine length rather than anything else.

    I take it your powder load is a minimum and that you intend to work up and that you've seen no pressure signs with any you've shot so far?

    By pushing the bullet further into the case you, potentially, increase the pressure as you reduce the volume of the case so if you were inclined to seat the bullet deeper in the case then you would need to start with the book minimum load a work up again if you wanted to be safe. If you are seeing pressure signs with your current load then, clearly, it would be unwise to do anything that could potentially increase the pressure.

    I use the 150 grain Hornady Spire Points in 308W and seat them to the book recommended length (by the manual I have) of 2.735 which puts the "crimp mark" in just about the right place, I'm running a book max powder load and see 3000fps with no signs of pressure, great accuracy and good brass life. It probably means I have a little more of the bullet in the neck of the case than you and that gives me a little confidence in the robustness of the round, it would be a pain to have the bullet drop out at a bad time.
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  5. #5
    I gave a reloading lesson to one of the clerks at the Trading Post. Without his rifle present, we loaded 40 rounds of 308 ammo. Seating depth of the 165 grain SST bullets was simply with the parallel sides of the bullet seated level to the neck-shoulder junction.

    The brass was Small Base resized, trimmed, loaded with a starting charge of IMR 4064, the bullets seated as described and crimped. They were the most accurate loads he ever shot and we never laid hands on the rifle until the loading was finished.~Muir

    PS: I load that same 4895 and the 150 grain SST for my daughter's 30-06. I determined the seating depth the same way: Parallel sides of the bullet to the base of the neck.
    Last edited by Muir; 30-10-2013 at 03:09.

  6. #6
    Yes working up from minimum load 43 grains the rifle is a styer pro hunter mountain.
    ​i have reloaded for .222 and found for my rifle the minimum load was the most consistent so stuck to that

  7. #7
    The 308 is about the most reloader friendly calibre ever made, 2,800 as good a start point as any.

  8. #8
    forget the crimping groove , seat to 2.800 and crack on .
    I'm of the opinion that crimping grooves are for machinegun ammo !
    Right where's those stones , I'll start !

  9. #9
    The MINIMUM OAL is correct for your powder/bullet weight configuration at 2.800" as previously stated.
    To determine MAXIMUM OAL proceed thus;

    1. - With a brass case previously fired from the rifle in question, de-prime it, clean it, re-size the neck and length.

    2. - Insert a bullet head by hand so that it is barely entered.

    3. - Gently place the assembly into the chamber and carefully close the bolt fully. This will place the bullet ogive onto the lands and push the bullet head into the case meaning there is no dead space between the bolt face and the point where the curvature of the bullet head touches the lands.

    4. - Now, equally carefully and slowly eject the assembly into your hand to avoid disturbing the setting.

    5. - You can now measure the OAL - case head to bullet tip.

    6. - Take 10 bullet heads and measure them for length consistency and you will probably find a variance in the order of 5 thou. If this is the case you can deduct 15 thou. from the measurement at (5) above and seat all your heads at this measurement. By doing this you will find you are safely in excess of the MINIMUM OAL so avoiding the risk of over pressure whilst placing the bullet head close to the lands for improved accuracy.

    If you feel the need to ensure a good fit between bullet head and case why not consider finishing off with the LEE FACTORY CRIMP?

    I hope this helps.

  10. #10
    Distinguished Member 223's Avatar
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    Nov 2009
    Nr Newport (shrops)
    i used to load this bullet (150 sst) in 308 and i seated it at 2.840 super accurate in my 308 xbolt, the ring was no wear near the top of the case mate
    you might not be able to go that long in your gun thou
    Last edited by 223; 30-10-2013 at 13:51.

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