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7.62by39

Discussion in 'Rifle Country' started by chaddy, Jan 9, 2011.

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  1. chaddy

    chaddy Member

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    Is 7.62by39 the same as 223 or 308 or neither one? Or is it just that 7.62by39.
     
  2. 2ndAmFan

    2ndAmFan Member

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    Neither one. It's just 7.62x39. .223 is 5.56x45; .308 is 7.62x51.
     
  3. PT1911

    PT1911 Member

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    7.62X39 is a specific cartridge, as is the .223, and the .308... the confusing thing is when you start talking about the 5.56X45 and 7.62X51, they are the NATO versions of the 223 and 308 that are just different enough justify everyone arguing about whether or not it is safe to shoot one in the other.

    Case in point!!!

    They are different cartridges, but similar enough that in modern guns they are safely interchangeable.... then comes the guy who says it is safe to shoot 223 in a 5.56 chamber but not the other way around because NATO rounds are higher pressure and have different case wall thickness, but somehow this pressure does not translate to the X51 v 308 argument... prepare to be confused.

    Drumroll please!!!
     
  4. brandon_mcg

    brandon_mcg Member

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  5. Zanad

    Zanad Member

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    7.62x39mm is a Russian intermediate cartridge introduced in the closing days of WWII. in terms of ft·lbf, the cartridge is around 2000 ft·lbf give or take. it fires a 30 cal bullet at around 2400fps at the muzzle. it is similar to lower powered 30-30 guns and acts as such(high arc and drops like a stone after a while).

    223 or 556x45mm is the current military cartridge used with small arms such as the ar-15. in terms of ballistics the .223 fires a .22 cal bullet @ 3000 fps and has an energy of approx. 1600 ft·lbf. its a relatively flat shooting cartridge and has little to no recoil.

    .308 or 7.62x51 is the hardest hitting out of all of them. its a larger cartridge than either of the two. not sure on ballistics on this one.(haven't done my homework.)


    7.62x39 is not the same as any of the other 2 you mentioned.
     
  6. bigfatdave

    bigfatdave Member

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    Cartridges are easily looked up on Wikipedia, it tends to have info on common loads (weight/velocity) the lineage of the cartridge, compatibility possibilities (not always available), and common guns chambered in it.
     
  7. JDMorris

    JDMorris Member

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    5.56 Nato is not safe to shoot in a .223 chambered rifle, it has a higher pressure and will cause serious problems..
    .223 is safe to shoot in a 5.56 chambered rifle, it has a lower pressure, no big deal.
    Some AR-15's have a "Wylde" chamber, cut to be the middleman of .223 and 5.56, In my opinion, the solution for us casual shooters, however many target shooters want a .223 chamber, and alot of "Tactical" guys, and the Military, want a 5.56 barrel.

    Now for .308/7.62 Nato..

    7.62 Nato, is safe to shoot in .308 chambered rifles, because it has a lower pressure, no problem..
    .308 has a higher pressure than 7.62 Nato, however, many people shoot .308 in their 7.62 Nato chambered Garands, and M14/M1A's..




    7.62x39 is 7.62x39, simple as that, doesn't interchange with anything.
     
  8. nalioth

    nalioth Member

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    To help you out in the future:

    In cartridge terminology, the first number is the diameter of the projectile.

    The second number is the case length.

    7.62x39 = A .30 caliber projectile in a 39mm case.
    5.56x45 = A .22 caliber projectile in a 45mm case.
    7.62x51 = A .30 caliber projectile in a 51mm case.
     
  9. W L Johnson

    W L Johnson Member

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    Nope, 7.62x51 and 308 have the same pressure. You may have seen 7.62x51 as being 50,000 psi, but it's 50,000 CUP (copper units of pressure), that's because 7.62x51 (7.62 NATO) was tested using the crush copper method. People keep changing CUP to PSI without converting, which starts the chicken little effect on the internet. There is however a slight head space difference which only is an issue if your head space is borderline.
     
    Last edited: Jan 9, 2011
  10. macadore

    macadore Member

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    Europeans designate a cartridge on the diameter of the bullet (projectile) by the length of the case. A 7.62x39 has a bullet with a diameter of 7.62 mm on a case that is 39 mm long. In the U.S. we still use inches. 7.62 mm is .308 inches so the diameter of the bullet in a 7.62x39 is the same as the diameter of a .308 Winchester. At one time we measured the diameter of the lands in the rifle barrel ( http://en.wikipedia.org/wiki/Rifling) rather than the diameter of the bullet so we referred to the .308 bullet as a 30 caliber. The 7.62x39, the .308 Winchester, the 30-06, and several other cartridges have bullets with a diameter of 7.62 mm/.308 inches. However, that's where the similarity ends for most of them. Bullet wights, case sizes, and case shapes differ widely.
     
  11. Davek1977

    Davek1977 Member

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    Which is ALMOSt right...aside from the 7.62x39 ACTUALLY using a .311 diameter bullet.....because nothing in life can be THAT simple, especially when it applies to cartridge designations!!
     
  12. nalioth

    nalioth Member

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    Wasn't trying to teach an engineering or history lesson, just trying to explain why some cartridges are represented the way they are.
     
  13. Davek1977

    Davek1977 Member

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    I realize the intent...just couldn't help myself...I apologize
     
  14. Don357

    Don357 Member

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    If you really want to confuse things,:banghead: try to explain why some 8mm Mauser/7.92x57 rounds have a .321 bullet and others have a .323 bullet.:neener:
     
  15. chaddy

    chaddy Member

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    So if I buy a ar do I get nato or 223?
     
  16. PT1911

    PT1911 Member

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    AR is chambered (most likely) in 5.56 and therefore it is safe to shoot either one... it is only the rifles that are specifically chambered in .223 (most will be target/varmint bolt guns) that you (supposedly) have to worry about...
     
  17. W L Johnson

    W L Johnson Member

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    And don't forget there are in-between 5.56/.223 chambers. They go by various names depending on the manufacture, Wylde (I think Rock River) and Armalite chambers come to mind. I think Bushmaster may have their own too.
     
  18. PT1911

    PT1911 Member

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    True, but from my understanding the only chamber that it is "unsafe" to fire a 5.56 from is specifically a .223. the "in-betweens" and 5.56 can shoot either safely... I am far from an expert in this. This is just what has come to be my understanding in the matter.
     
  19. W L Johnson

    W L Johnson Member

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    That's my understanding too.
     
  20. PapaG

    PapaG Member

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    Don357....some 8mm Mauser rounds have a 318 diameter bullet.
     
  21. HOOfan_1

    HOOfan_1 Member

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    Yeah, the .303 British, 7.62x54R, 7.62x39 and 7.7 Arisaka all use basically bullets of the same diameter +/- .001 inch depending on individual guns.

    Yet the .308Win/7.62x51 are use a smaller diameter.

    It's about as confusing as English sometimes

    the 7.92x57 I did...that is the original Mauser with the long rounded bullets...the WWI and WWII version 7.92x57 IS was .323
     
  22. jimmyraythomason

    jimmyraythomason Member

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    Many or most Mauser 98 rifles were bored out to .323 by 1905.
     
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