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.308 v. 7.62 NATO

Discussion in 'General Rifle' started by Philip, Apr 11, 2008.

  1. Philip

    Philip G&G Newbie

    so i hear that you shouldn't use 7.62 nato round in a a .308, but you can use .308 in a military rifle?

    something about the rounds are slightly different?

    i always thought a 7.62 nato was a .308, just like a 5.54 is a 223.

  2. phoenix79

    phoenix79 G&G Newbie

    Dimensionally they are the same, it's the pressures involved that are different. In the 5.56/.223 the 5.56 can be loaded to higher pressures than the .223 so you can shoot .223 in a 5.56 gun but not the other way around. As for 7.62NATO vs. .308, I'm not sure which is at the higher pressure.
  3. wunhunglo

    wunhunglo G&G Newbie

    Other way round, I'm afraid, with the opposite for 5.56/.223.

    While the 7.62mm NATO cartridge has a maximum chamber pressure of approximately 50,000 psi, in the SAAMI book the .308 Winchester has a MAP (maximum average product) pressure of approximately 62,000 psi. This is not to say that all .308 Winchester loads will develop such pressures, merely that they would be within manufacturing tolerances if they did so. Firing .308 Winchester ammunition in a firearm specifically chambered for the 7.62mm NATO risks damage to the firearm and injury to the shooter.
  4. mitch_mckee

    mitch_mckee Suspended

    I've heard the opposite. The 7.62 NATO is OK in the .308 Win. and I've done so for at least ten years in commercial bolt guns.

    However, SAMMI doesn't list it as a problem.

    SAAMI | Unsafe Arms and Ammunition Combinations
  5. just_a_car

    just_a_car G&G Newbie


    In addition, the external dimensions of the cartridges are the same, BUT the 7.62 NATO round has a thicker case wall than the commercial .308Win case, thus giving a smaller internal case capacity. This is one reason for the lower pressures of the NATO round. The thicker cases are designed to stand up to the fully-automatic and violent actions of military battle rifles such as the CETME.
  6. cma g21

    cma g21 G&G Regular

    The Gun Zone -- .30 Caliber Ammo
    Collecting and Shooting the Military Surplus Rifle (2006) -
  7. Philip

    Philip G&G Newbie

    so can you or cant you use surplus 7.62 nato in say, a winchester or remington .308?
  8. wunhunglo

    wunhunglo G&G Newbie

  9. Philip

    Philip G&G Newbie

    it just wont reload right?

  10. just_a_car

    just_a_car G&G Newbie


    Use 7.62NATO in .308Win Firearm: A-Okay.
    Use .308Win in 7.62NATO Firearm: Not recommended, but I do it in my CETME without issue.

    Reloading any case requires the case to be in serviceable condition. The autoloaders can have violent actions which damage cases, thus making them useless. Bolt guns will be much more forgiving and leave brass reloadable.
  11. Philip

    Philip G&G Newbie

    ok, my dad heard from guys at his work that you dont wanna use 7.62 in a .308, but i'll hafta tell him that its the other way around
    Last edited: Apr 12, 2008
  12. mitch_mckee

    mitch_mckee Suspended

    I do on a regular basis. Remington 700 ADL .308. I shot more mil surplus 7.62 NATO through it than commercial. Still shoots just under 1 moa with good ammo.
  13. billy

    billy G&G Evangelist

    my saiga rifle says on the barrel
    7.62x51/.308 win
  14. mitch_mckee

    mitch_mckee Suspended

    This Remington says &.62 NATO (.308 Winchester)

    Remington Model 40-XB™ KS
  15. Tigercat200

    Tigercat200 G&G Evangelist

    I shot prairie dogs with 7.62 NATO surplus in my Savage 110FP. They only thought they could hide behind their dirt piles.
  16. cma g21

    cma g21 G&G Regular

    The only .308 rifle I've ever had experience problems using 7.62 NATO is an H&R single shot. Would sometimes fail to extract (a common problem with the H&R's).

    The problem's I've seen or had using .308 in a 7.62 NATO rifle were:

    FR-8: split case necks (chamber too long for .308), but NATO ammo works fine.

    Enfield 2A: Sticky extraction with .308 (also a too long chanmber), again NATO ammo worked fine.

    CETME: Case separation with a (federal) .308. No damage, and a broken shell extractor easily removed the case remnant. 1000 + rounds of NATO w/o a problem.
  17. roundman

    roundman G&G Newbie

    I have a Indian made .308 Enfield ( not a modified .303 rechambered to a .308) and I've talked to several gun collectors of military rifles . I was told that my enfield was built to handle the pressure of the nato or the win. rounds because during the war you got ammo from several places and you did'nt know what the load actualy was.It's just my 2 cents worth, and I'm still learning and I've learned a lot from yall.
  18. Zombie Hunter

    Zombie Hunter G&G Newbie

    It is my understanding that there are head space differences in the chambers of the .308WIN and the 7.62NATO rifles.
    I own an Springfield M1A 7.62nato and Savage 110 FP .308win.

    The NATO rifle has a slightly longer chamber. Because of the thicker walls and lower pressures of the nato round , it will form fit or fire form (if you will) to the chamber. This is why reloaded nato casings (fired first in nato rifle) will not fit in a .308 rifle.

    Commercial .308WIN cartridge has thinner walls and higher max pressure.
    Because of this the .308WIN casing may rupter as it expands to fill the longer chamber of the NATO rifle.

    I have used military surplus in my .308 for years and never had a problem,
    nor have I ever heard of a problem using surplus 7.62NATO in a .308 rifle.

    Bottom line (without all the details of chamber sizes,diagrams,gauges and
    pressures involved) is :

    OK to use surplus 7.62Nato in .308 rifle.

    OK to use reloaded 7.62Nato in .308 rifle(as long as it was not "fired first" in NATO rifle and then reloaded.

    NOT Recommended to use commercial .308WIN in 7.62Nato rifle (may rupture and may cause rifle damage at the least).

    OK to use reloaded .308WIN in 7.62Nato rifle as long you DO NOT exceed
    max pressure of rifle. Never trust others reloads.

    I only use my own reloads. I know it sounds paranoid,but I've seen too many "accidents" over the last 26 years involving people using a trusted friends reloads
  19. tkarnes

    tkarnes G&G Newbie

    I reload .308 and .223 and most civilian ammo is hotter than military. You can damage operating rods on M1A's shootint to hot a load. The majority .308 guns are bolt guns and they can stand higher pressures. I shoot my palma rifle 155 gr at 2900 fps. I wouldn't consider shooting my M1A over 2750fps with the same 155 sierra match king. I have a savage mod.10 and I've shot a bunch of military surplus with no problem.
  20. Bart B.

    Bart B. G&G Newbie

    SAAMI specs on .308 Win. ammo can be seen at:

    where max average pressure is listed as 52,000 CUP or 62,000 PSI; there's a section on both pressure measuring methods' specifications.

    Military specs on 7.62mm NATO ammo can be seen at:

    where max average pressure is listed at 50,000 for M80 ball ammo. It's listed in the column headed "PSI" but it's actually CUP or copper units of pressure. Lake City Arsenal confirmed this to me some years ago; they often talk and print "psi" but use copper crusher gage systems in precision pressure test barrels to do the tesing. Which means it's about 60,000 PSI on electronic pressure transducers.

    And 2,000 pounds of average pressure difference isn't much at that level. Pressure test cartridges produce about 40% more pressure than standard maximum loads.

    Zombie Hunter mentions:
    I wonder why the US military rifle teams orderd thousands (millions?) of rounds of commercial .308 Win. match ammo to shoot in their M14NM's and M1's mil spec chambers. No problems whatsoever. And some ammo they shot had peak pressures close to what pressure test cartridges produce.
    Last edited: Feb 7, 2010
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