.308 or NATO 7.62

Discussion in 'Ammunition & Reloading' started by net-work, Dec 10, 2013.

  1. net-work

    net-work New Member

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    Someone at my gun club gave me a lot of mixed ammo; .308 and .7.62 NATO thinking that I could fire it all my rifles. My DPMS LR-308 and Browning Lever rifle will only shoot .308 and that's per info I got directly from those two manufacturers. Both advised not to use the 7.62 NATO. Is there a way that I can sort the .308 and the 7.62 NATO ammo so that I can keep just the .308 ammo that I can use? Thanks in advance. Regards. Jerry
     
  2. c3shooter

    c3shooter Administrator Staff Member

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    Jerry- first, welcome to the forum- when you get a moment, stop by the intro thread and say hello.

    In general- A rifle chambered for .308 Winchester can ALSO safely shoot 7.62 NATO. However, a rifle chambered for 7.62 NATO will not always be safe to shoot .308 Winchester. It is the opposite of the 5.56 and .223 situation.

    This is a 7.62 NATO round. Note the circle with the cross? Symbol that indicates a STANAG (Standard NATO Agreement) cartridge.

    F_308.jpg
     

  3. JonM

    JonM Moderator

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    Agreeing with c3.

    7.62nato will shoot with no problems out of any 308. May not get great accuracy out of a 308 since most NATO is 147grain which performs bleh out of. Typical 1-10 twist 308win barrel. 7.62nato is 1-12 twist and works well with anything up to 168grn.

    The real diff tween the two other than rifling twist rate is the 7.62nato has a shorter lead on the throat.

    The exception to this rule is the fn scar17 which has a 1-12 twist and a 308win throat and marked 7.62nato

    If yours is marked 308 win you can shoot both you just won't get good results with the NATO which is why dpms says don't use it. They don't want people calling tech support btching about poor accuracy
     
    Last edited: Dec 10, 2013
  4. mseric

    mseric New Member

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    I can think of no reason why any gun manufacturer would tell you cannot shoot 7.62 ammo out of a 308 rifle. After all they are identical. Unless they are concerned about the bullet itself as if it is some king of tracer or steel jacket.

    Take a look at this Federal ammo. One is a 308 Winchester and the other is 7.62 NATO. Note, the same weight bullet generates identical velocities for both. The only way that can happen is if they are operation at the same pressures.

    http://www.midwayusa.com/product/95...grain-sierra-matchking-hollow-point-boat-tail

    Technical Information
    Caliber: 308 Winchester
    Bullet Weight: 168 Grains
    Bullet Style: Sierra MatchKing Hollow Point Boat Tail
    Case Type: Brass


    Muzzle Velocity: 2650 fps
    Muzzle Energy: 2619 ft. lbs.


    http://www.midwayusa.com/product/95...nition-762x51mm-nato-168-grain-open-tip-match

    Technical Information
    Caliber: 7.62x51mm NATO
    Bullet Weight: 168 Grains
    Bullet Style: Open Tip Match
    Case Type: Brass

    Ballistics Information:
    Muzzle Velocity: 2650 fps
    Muzzle Energy: 2619 ft. lbs.


    I can't imagine why DPMS or Browning would object to either one of these in their rifles.:confused:
     
  5. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    The issue is not necessarily peak pressure, but pressure curve. The two listed cartridges are not necessarily "identical". Velocities can be reached differently. Some guns (like the M1-A) are not suitable for the slower powders used in many commercial .308 rounds. Pressures peaking at a different point can wreak havoc on the operating rod.

    Just because a domestic manufacturer labels something as "7.62 NATO" does not mean it is actually made to NATO specs. There is the disctinct possibility something may be mislabeled.

    I do not believe there is a NATO standard for 7.62 X 51 168 gr OTM ammo.
     
  6. danf_fl

    danf_fl Retired Supporter

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    Have you wondered why Federal offers a .308 Win and a 7.62X51?

    If they were the same why waste money to have two different labels for the same round?
     
  7. mseric

    mseric New Member

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    This is a good point, cept it's backaswards as to the OPs situation. He was told not to shoot 7.62 ammo in his 308, not the other way around.

    IMR-4895/WC-846 was one of the powders specked out in 7.62 Ball M118 ammo. Noting about this powder and it's pressure curve is going to cause issues with the OP's Browning lever gun or his 308 DPMS or even the M1-A.

    If Browning and DPMS told him to not use Winchester Supreme ammo or other high performance ammo, maybe, but not mil-spec 7.62 ammo. No way any of that is going to bend an op rod. Besides, neither of his rifles have Op rods.
     
  8. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    I went to the Browning web site and reviewed the owners manuals for both the pre-93 BAR and the BAR Mk II. I saw NO reference to the caliber conflict.

    If this was actually a part of the OP's manual I would like to see the scanned pages. Otherwise we are about to be done here.
     
  9. JTJ

    JTJ Well-Known Member Supporter

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    I got hold of some South African 7.62x51 that was definitely on the hot side. I noticed the difference in recoil over the 308 rounds in a Savage 10. Some of this so called surplus may be out of spec rejects.
     
  10. 303tom

    303tom Well-Known Member

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    Because you people won`t shoot .308 in your 7.62x51 rifles & you think they are going to miss out on that money. I have a friend who works at Lake City & says that most of the time when they switch from .223 to 5.56 the only thing they change is the bullet & head stamp !............
     
  11. c3shooter

    c3shooter Administrator Staff Member

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    FWIW, the NATO cartridge case is thicker in the base of the case- and while the external dimensions are the same, the internal volume is less. When shooting NATO loaded ammo, no biggy. If you RELOAD, and use .308 Winchester powder data, but put it into a NATO case, pressures will be higher.

    But circling back to the original post, I know of no .308 Winchester chambered rifle that cannot safely shoot standard .7.62 NATO ammo. And NATO ammo will be identified by the circle with the cross. If the headstamp says .308, it is NOT a NATO cartridge.
     
  12. JonM

    JonM Moderator

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    Yeah case volume is already poor in the 308win and shrinking it more for nato makes it really tough
     
  13. kusterleXD

    kusterleXD New Member

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    The biggest difference not mentioned so far is the max pressure that SAAMI lists to differentiate between the two. 7.62x51 NATO has a max pressure of 50,000 PSI whereas 308 Winchester has a max pressure of 62,000 PSI.
     
  14. mseric

    mseric New Member

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    Max pressure for the 7.62 is 50K CUP not psi. Max pressure for the 308 is 52K CUP which equates to 62K PSI.
     
  15. JonM

    JonM Moderator

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    the reason its lower is because of the old military m14 rifle cant really handle the higher pressure commercial 30-06. the oprods like on the m1 garand tend to bend using commercial 308win.

    the reciever and barrel can handle it just fine so long as shorter 150-168grain rounds are used but the gas system cant

    the new production m1a from springfield marked 308win are different in they use a safe gas system for higher pressure rounds. however there are a lot of people who foolishly replace the springfield gas system with gi surplus making them unsafe to fire modern 308win even if marked 308win...
     
  16. 25-5

    25-5 New Member

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    150-168grain rounds are used but the gas system cant the new production m1a from springfield marked 308win are different in they use a safe gas system for higher pressure rounds. however there are a lot of people who foolishly replace the springfield gas system with gi surplus making them unsafe to fire modern 308win even if marked 308win...[/QUOTE]

    Thanks Jon
    I have read this thread with interest. Knew most the info but wondered about my SA M1A marked as .308. You answered before I could ask.
     
  17. mseric

    mseric New Member

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