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7.62 X 39 is really a 308

Discussion in 'General Gun Discussions' started by johned, Mar 28, 2012.

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  1. johned

    johned Member

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    Well,

    Having beat this to death, and my exhaustion, I finally have a feel for the situation. My original dilemma was "can I put a 308 bore on a 7.62 X 39" gun. Lots of good people have said "NO" because the 7.62 X 39 bullet is "oversize" and would be dangerous. That is certainly good solid advice. Others have said that 309 or 310 should be OK and that is probably true, as well. So who will I kill? Turns out this is a really deep question with some surprising answers. Follow this:

    The 7.62 X 39 round is only "sorta" correctly dimensioned. ACTUALLY the round is ....308( .5 or 9) at the leading part/front of the bullet after the Ogive. In the final 5 or 10 thousandths of the bullet the diameter swells to .311. That is like putting a gas check on the rear. With that design it would perform, ballistically, like a full .311 bullet in a .312 or 311 bore. It would also fire safely in a .308 bore. Recently learned that Savage made a 7.62 X 39 that had exactly a 308 bore. No alarms going off in the community about the Savage bolt guns being lethal to the shooter. Also, no "WARNING odd size bore" stamped in the barrel. Others have done this exact same thing with other firearms, including the VZ 58 foundation design and all has worked out swimmingly. The VZ 2008 had a 308 bore and the other Century VZ 58 clones, using us made barrels, had 308 bores. What a cluster FXXX, right? Conundrum...at least...right. The design of the Russian 7.62 X 39 round is the answer as it is 308 "mostly".

    Here is the real danger. If I thought that .311 or .312 Russian bullet was actually that size....I might be tempted to HAND LOAD .312 bullets and use them in a 7.62 X 39 chamber. And that might simply explode in my face.

    Thank this guy:

    Minesweeper3433

    Trade Count: (+6)
    Senior Member
    ****
    Posts: 304

    Bullit OVERSIZE
    « Reply #21 on: Yesterday at 11:22 PM »

    Quote

    Built a 7.62x39 bolt gun on an mini mauser for shooting surplus ammo out of using a 308 bore. Went with 308 as on measuring rounds we pulled found that only the last 5-8 thousandths were larger than 308. Almost like a skirt. That gun shoots great to this day with steel cased ammo or whatever else we feel like putting in it. We put a long 1 degree throat in it as well when ordering the reamer. Although I was always taught that the AK series of rifles had a long throat for that reason. This was however from an instructor at Aberdeen that I didn't hold in to high regard. Will pull a few soviet rounds over seas here today if I can get my hands on a few.
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    Old guns like old friendships are long retained and must be constantly renewed. James V. Howe The modern gunsmith Pub. 1934 People where smarter before I was born.

    Navy...might have known...right?

    Good luck,


    John
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  2. armoredman

    armoredman Member

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    I wanted to see, too. So a cartridge, a Wolf HP, gave it's life so that others may learn. First the powder reminded me of H-4895, but surely wasn't anything close. :) The boat tail bullet, (122.5 grains, 1.29 inch long, BTW), measured .308 up to the red sealant band. From the band a stretch of .24 appeared to measure .310, then it tapered to the boat tal. At no point was the bullet .311 or .312.
    No pictures, sorry, that hit my camera took wiped out the macro function.
     
  3. 303tom

    303tom member

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    Yes 7.62mm is .308 inch ie; .30 caliber............Actually it is little a bigger, like .312. but it is still a .30 cal.
     
    Last edited: Mar 28, 2012
  4. dastardly-D

    dastardly-D Member

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    slightly off

    Not exactly what you're doing,but I have reloaded regular Sierra 308 into a Russian 7.62x54R and had no problems at all.Aren't they the same diameter bullet ?
     
  5. solvability

    solvability Member

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    I have a bunch of pulled bullets from the 7,62x54r can I load the bullets in 308 or 30-06? That would be useful.

    I know when I handloaded for 7,62x54r I got the best accuracy from Hornady 312 bullets like I use for my Enfield - hmmm.
     
    Last edited: Mar 28, 2012
  6. Jeff F

    Jeff F Member

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    I have loaded .308 bullets in the .303 British with fair to good results then I learned about paper patching and have had very good results. When the Ruger Mini 30 first came out it had a .308 bore, I have never seen any reports of any problems with the surplus 7.62 x39 that has .311 or .312 bullets.
     
  7. AJumbo

    AJumbo Member

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    Marlin made a run of 32-20 lever rifles with .308 bores, and they fired standard 32-20 bullets just fine.
     
  8. 303tom

    303tom member

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    I shoot .32 ACP in my .308 with an adapter & they shoot great.........& they are 7.65x17.
     
  9. Romeo 33 Delta

    Romeo 33 Delta Member

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    I think the 7.62 X 39 is really more .309/.310" as a rule.

    I don't see why being .002" overbore in a strong action with reasonable loads and a 123gr bullet would be a problem ... HOWEVER

    When I feel the need, I take some of my .309/.310" bullets and run them through a .308" Lee sizer die ... very little effort is required to do this, so that's telling me that the jacket is not overly thick (like when I take my Hornady Carcano .2675" bullets down to .2660" ... that takes a bit of effort because of the thicker jacket) and I'm not changing the diameter by all that much.

    Now I've been told that this causes problems with the jacket/lead core set up, but I've not seen any accuracy problems ... but then I'm shooting at 50 and 100 yards so maybe it just doesn't show up at that distance.
    Just my 2 cents worth ... your results may be different.

    I believe that Ruger used a .308" barrel on the Mini-14 ... but with a longer throat to help ease the larger bullet through. I don't know about the Model 77. I have both but never checked the 77's groove diameter. I'd be surprised if they would have opted to have two different barrels for the same caliber???
     
  10. Fishslayer

    Fishslayer Member

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    I have one of those early Minis. I've put a hunnert or so of the Yugo milsurp x39 through it. Works just fine.
     
  11. R.W.Dale

    R.W.Dale Member

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    I shot hundreds of rounds of monarch through my 7.62x39 savage bench gun I built. Even after I reamed it to an "improved" version of 7.62x39

    posted via mobile device.
     
  12. mac66

    mac66 Member

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    My original Mini 30 has a .308 bore and I shoot military x39 ammo in it with no problems.
     
  13. Driftertank

    Driftertank Member

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    Seems to me, if it really concerns someone, it shouldn't be to hard to have a barrel gauged. As has been previously stated, i don't think .002-3" would cause a problem, as when loading a .310-.311 diameter bullet for a .308 bore, unless you're running close to pressure peak. I WOULD, however make sure to have the bore gauged before trying to load .312 (nominal) bullets, as they'd probably cause issues in a .308 bore.

    I wouldn't recommend loading 54r bullets in .308 without mic'ing them.

    I would think many US ammunition manufacturers would likely lean towards .308 bullets, or at least tapering as notid by the OP, since loading overbore rounds could cause safety issues, while loading underbore only hurts accuracy.
     
  14. DoubleTapDrew

    DoubleTapDrew Member

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    I read at some point in time on some forum (probably here) the difference is where it's measured. Americans measure the bore size from the diamater between the lands and the ruskies measure the diamater from the grooves. So the bullet diamater is the same in spite of the claimed bore diamater.
    Not sure if that's true or not but would explain the .308 vs .310-.312 stuff.
     
  15. ApacheCoTodd

    ApacheCoTodd Member

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    Damn, a 7.62 X 39 is a 7.62? Sure, and Pluto is a planet!:D
     
  16. 303tom

    303tom member

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    I was weighting on someone to speak up that knows what they are talking about, way to go Drew...........
     
  17. R.W.Dale

    R.W.Dale Member

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    The nomenclature about bore and groove diameter means essentially nothing beyond the nonsensical way cartridges are named.

    Think of this
    7.62x39
    7.7x58 jap
    7.65x53 Mauser
    .303 British
    7.62x54r

    All the above use the same bullet diameters plus or minus a couple thousandths

    Then you have
    7.62x51mm
    7.5x55
    7.5x54
    300 sav to mag
    30-30 to 30/06

    These all use the same bullet diameter nominally

    But the really important tidbit to understand is 7.62x39 runs on the very smallest side of the topmost list and can indeed be quite happy shooting bullets from or being shot in barrels for the bottom list.

    Russian 7.62 tends to have a slightly larger groove diameter than what we call 7.62 in the west .310 vs .308"

    But the Russians also use a deeper rifling and most of the time will have the same .300" bore that we call 30 caliber here.

    posted via mobile device.
     
    Last edited: Mar 29, 2012
  18. 303tom

    303tom member

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    Damn Dale, your right again.............
     
  19. DoubleTapDrew

    DoubleTapDrew Member

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    Sooo...
    I should stop shooting 7.62x39 out of my M1A? lol jk :p
     
  20. Driftertank

    Driftertank Member

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    On a related note, a friend texted me the other day asking if there was another name for 7.62x39, because he was trying to buy some ammo for his Tantal, and the chick at the gun shop he went to said .308 was the same thing.

    I told him no, and regardless of whether she was stupid (or rather ignorant), he shoul buy his ammo, and anything else firearms-related, somewhere else...
     
  21. 303tom

    303tom member

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    Yes, .30 Caliber Russian..................Not .308 Winchester.
     
  22. Driftertank

    Driftertank Member

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    Ah, but 54r is also ".30 caliber Russian," and it won't work in his gun either. Also, since i've never seen a box of ammunition labeled ".30 caliber Russian" i wouldn't consider it a legit term for 39. Especially when dealing with someone who thinks .308 Win is the same thing...
     
  23. Cemo

    Cemo Member

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    My RCBS reloading die set came with two sizes of neck sizers, one is .308 and the other is a little larger at .311.
     
  24. dexter

    dexter Member

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    Hornady 7.62 123gr sp is marked .310 on the box.It also mics .310.
     
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