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308 col

Discussion in 'Ammunition & Reloading' started by IheartGUNS, Apr 11, 2013.

  1. IheartGUNS

    IheartGUNS WaCo Well-Known Member

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    So i'm helping a friend of mine reload 308's for his m1a, heres the problem:

    I trimmed the cases to 2.005, seated the bullet at the cannelure, measured the col(2.720) and its below the min col(2.800).

    -150gr fmjbt w/c hornady bullet
    -rem once fired cases
    -36gr varget
    -hornady 7th ed reloading manual

    Would it be safe to shoot? Somebody told me it should be safe because we're loading at 36gr. which is a low charge.

    What gets me is why is the col short? Defective bullet?
     
  2. jib

    jib Central OR Active Member

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    Are your sure that 2.8" isn't the max COL ?
     
  3. IheartGUNS

    IheartGUNS WaCo Well-Known Member

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    Max is 2.810 min. is 2.800
     
  4. deadshot2

    deadshot2 NW Quadrant WA State Well-Known Member

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    As long as you aren't compressing a load that shouldn't be compressed there really isn't a "too short" when it comes to OAL.

    It may screw up accuracy with the extra jump. Shorter bullets will almost always end up with a shorter OAL.

    For the most part, 2.800 is tossed around as the .308 Design standard because this is what feeds from internal magazines best.

    A good guideline when building a load is to hold a bullet up alongside the case, line up the "pressure ring" which is the bottom radius of a flat based bullet or the top edge of the boat-tail, with the junction of the case neck/shoulder. Mark the bullet and insert into an empty case until the line is at the case mouth. Measure that OAL and it's your new minimum. Again, as long as it's not compressing the powder load unless it it a powder like Varget that can be compressed.
     
  5. BillCh

    BillCh Vancouver Active Member

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    You're probably not going to blow anything up with that load. I'd be surprised if it will cycle the action. Take a wooden dowel with you when you go to try these, just in case you have a squib.
    The COL of 2.720 - 2.740 is fine for that bullet. I know powder is hard to come by these days but you should really use a powder better suited for the M1A gas system. Don't get me wrong, Varget is good and all, just not for the M1A.

    B
     
  6. Benchrest

    Benchrest The Desert Planet Well-Known Member

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    IheartGUNS

    Not knowing what bullet you're using I based your load data on Hornady' 3037. With that, QuickLOAD says you're at 28,000psi (22 inch barrel).

    Certainly not definitive, but the load seems very safe.


    Jason