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7.62x51 versus .308

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  • 7.62x51 versus .308

    Trying to find a straight answer for the differences between 7.62x51 and .308. I've heard they're the same, and I've heard that a 7.62x51 rifle can shoot either but a .308 rifle should only fire .308 or may sustain damage?!? What's the deal here?

    Purpose of comparison is for buying ammo for both a DSA SA58 and a Savage .308.

  • #2
    both will eat whatever you feed it

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    • #3
      Thanks for the prompt reply [img]smile.gif[/img] This is what I was hoping to hear.

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      • #4
        I had the same worries last year in regards to what kind of amm is safe for my Israeli Mauser - 7.62mm NATO or .308 Winchester.

        In the end, both 7.62mm NATO and .308 Winchester are safe to use for my Israeli Mauser and I feel a little bit more comfortable in using commerical .308 Winchester rifle ammo for my rifle.
        If you want peace then prepare for war - Ancient Roman maxim

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        • #5
          FWIW I have a lever-action Savage 94 in 308, and I have shot several rounds of NATO 7.62; However, when I bought a battle pack of that South African 7.62 from Cheaper Than Dirt, it wouldnt feed very well. I ended up giving it away to Trifecta and his FAL gobbled it up.

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          • #6
            Typically, the theory that they are the same is correct.

            But one thing to keep in mind. 7.62x51 is a standard load. One bullet, one velocity, to meet NATO specs.

            If you start putting heavy bullets with heavy loads that are designed for a new .308 into an older bolt action 7.62x51 conversion. (Izzy, Spanish or Chilean Mausers come to mind readily) you may be approaching the design limits of the rifle, given the fact that the metallurgy skills back in the late 1800's to early 1900's when those were made didn't contemplate reboring the chamber.



            The odds are in your favor, but for myself, I stay with 150g ammo and standard pressures, with anything but the Ishapores. (They were built for that caliber, much later in time. 10% overpressure isn't a factor with them.)

            The odds are against any problems, even with the older ones, but you should know that you are playing with those odds if you get enthusiastic with loads and bullet weights.
            Alle Kunst ist umsunst Wenn ein Engel auf das Zundloch brunzet (All skill is in vain if an angel pisses down the touch-hole of your musket.) Old German Folk Wisdom.

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            • #7
              Wikipedia ( http://en.wikipedia.org/wiki/.308_Winchester ) has this to say:
              While the .308 Winchester and 7.62 ◊ 51 mm cartridges are generally identical, there are minor differences in their case dimensions and chambering specifications that should be noted. The 7.62 ◊ 51 mm is smaller by a few thousandths of an inch in some dimensions. [citation needed] This can lead to excessive chamber pressures if a .308 Winchester cartridge is fired in a 7.62 ◊ 51 mm chamber. However, the opposite should present no problems.
              Of course, Wikipedia is not a definitive authority, but it is right most of the time.

              flashguy
              [FONT=Arial]When they ask me, "Paper or plastic?" I just say, "Doesn't matter to me. I am bi-sacksual." [/FONT]

              Texan by choice, not accident of birth

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              • #8
                Ahhh,
                The continuing controversy of 7.62x51 vs. .308 Winchester.
                There like twins. NOT identical twins, different in minor details.
                What I understand is this: 7.62x51 (NATO) is loaded to somewhat less pressure than commercial .308 Winchester. Other differences noted about size also apply. In weapons like my M1A & CETME I use only USGI/NATO type pressure ammo. The gas systems canít handle the extra pressure; it slams the bolt carrier back real HARD. Ouch. As far as bullet weights are concerned I know USGI (i.e. NATO) specs ammunition can range from the low 140s grain (Aussie) to as high as 173 grain USGI Match. Other loading with heavier bullets might be available at NATO pressure. Hornady is loading as low as 125 grain to function in the M1A/M-14 weapons. It should cycle in other weapons designed for USGI/NATO ammunition. In my Israeli K-98 in .308 I would happily shoot any military or commercial ammunition. Why? Because 98 Mauser actions are safely modified to handle Magnum cartridges. In my Ishapore .308 Iíll stay on the SAFE side and stick with USGI/NATO pressures. Plenty to work with there. The other rifles mentioned I would not go beyond USGI/NATO pressures when loading/shooting. If you want to load/shoot HOT .30 caliber stuff shoot something like 300 Winchester magnum. Itís built to take it.
                I tend to load on the conservative side. Iím looking for accuracy. Speed is no help if you canít hit the ďtargetĒ. I need ALL the help I can get.


                Hope this helps.
                Paul the Ammo Guy 8-)

                "Aim small, miss small".

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                • #9
                  I simply consider 7.62x51 Nato equals military and .308 equals civilian use and don't worry any farther than that.

                  And yes, they can be interchanged with some Caveats but that is up to each person.

                  7.62x51 in military and .308 in civilian rules will keep you happy.
                  Youth And Brawn Are No Match For Age And Treachery.
                  I'm Old And May Not Fight. I'll Shoot Instead.

                  USMC 1959/1963

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                  • #10
                    Those are interesting facts about the .308/7.62 NATO comparison. And the conclusion there is just the opposite of the .223/5.56x45 comparison.

                    The 5.56 military round is usually loaded to a higher pressure than .223, and the military-type rifles that chamber 5.56 usually have longer throats.

                    Bottom line is that .223 rounds can work in a 5.56 rifle, but not to try 5.56 rounds in a rifle designed for .223's, with shorter throats, that can spike pressures if the bullet can't 'jump' freely.

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                    • #11
                      I've been using 7.62mm NATO and .308 Winchester in several of my Israeli K98s for some time now. Never expreienced a problem.

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                      • #12
                        I believe with the M1A rifles, you need to be aware of the headspace. Mine checks out ok for either round, but since the pressure can be higher with SAAMI spect ammo, I usually stick to MilSurp stuff.
                        The execption is my SOCOM, which works fine with a limited amount of Federal Classic 150 grain SP, when I use it for hog hunting.
                        may the Bonnie Blue wave forever<br /><br />Nemo Me Impune Lacesset

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                        • #13
                          Re: 7.62x51 versus .308

                          I've shot both interchangably in everything from Remington 742's to FAL's to Bolt actions. I've haven't had problems even though they use a different set of guages to set headspace.
                          "some people never let their given word interfere if something they want comes along"
                          The real problem with the world are laws preventing culling.

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                          • #14
                            Re: 7.62x51 versus .308

                            my biggest concern would be the lighter conmmercial primers. 5.56x45 is interchangeable with .223 in normal useage.

                            7.62x51 is interchangeable with .308 in normal useage.

                            don't be a Woose.

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                            • #15
                              Re: 7.62x51 versus .308

                              I feel after examining velocities and primers over some years that the milspec .223Rem and .308W ammo is generally hotter here in OZ than normal own-loads for sporting use.

                              Occaisionally some milsurp ammo in .223/5.56 can be too hot for hunting/target firearms. Some of the Chinese Norinco was a case in point and the pressure/blast was excessive for B/A sporters, [we had reports of blown primers, excessive fouling and jams.] Cheap, but not nice to use in your new $1.6K rifle or be near on the range!

                              The most recent Aussie 7.62 manufactured is for the heavier/vehicle mounted MGs only, as all the Inf FALs have all been crushed here or more happily sold overseas; thus I would say this round from this source now could be too "hot" for our ordinary use? [Maybe a bit similar to the Vickers .303 MK8 and the supply of some MG 7mm Mauser the dealers got hold of 5 yrs ago and have subsequently given quite a few people scares on firing it from sporting firearms. Safety/headspace was also an important issue in older surplus Enfield/Lithgow .303 Mk1* ......only designed for Mk7 ammo!]

                              ADI/Mulwex in Oz (makes some of the US 'Hogdon' podwers range too) now makes all boxer primed ammo in these two cals. It also makes a 'pest exterminator' round for helicopter-shooting of pigs/goats/brunbies etc with MSSAs, having a soft-point pill, not FMJ. Good brass too I head for reloading.

                              The military industry I am assured here do not reload 7.62 or .223.
                              The specs have had careful safeguards built-in, as regards fit and leade etc as this ammo MUST work under all conditions of climate and even poor cleanliness/fouling/heat/dust/sand etc. This is way above normal sporting needs.

                              However in my opinion, while most mil-spec ammo is "loaded-up" to a high extent it should be OK in modern civillian or ex-mil arms and especially in the like of M98 .308 mausers from good manufacturers such as FN/Mauser etc.

                              Unfired dimensions should always be checked against your chamber. I had hightened pressures in S&B milspec ammo fired in a .303 No4 Mk2 Savage, due to the shorter/closer chambering on the local 'Sportco' target barrel fitted. [You could actually see the machine chatter/marks on the fired neck on the milspec ammo used. Extraction was sticky. I should have stopped after 2-3 shots, but didnt. No damage or head-space problems, but I was lucky].

                              However also bear in mind the milspec waterproofing of the projectile (may have to clean-off the glue/bitumen residue more frequently after firing from leade/neck area) and also the waterproofing of the primers and the crimping can present problems for civillian use. Also reloading can be complicated for sporting arms.

                              Just make sure you are not using milsurp "hot" MG or "special ammo" (EG -A.P.) and if it chronos high with a heavier recoil /report than usual, has any "stickyness" on extraction, flattened primers etc...take it back to the dealer who sold it to you..... or use the impact hammer/reloading bench and reduce the powder and/or alter the dimentions.

                              'Caveat emptor' really applies for all military surplus ammo - IMHO....
                              There is no Spring without Winter, without Mistakes there is no Learning. There is no Life without Death, without Doubts there is no Faith. There is no Peace without War, without Fear there is no Courage. For without Mistakes, Doubts and Fears there are no pathways to Wisdom.
                              Ron Owen.

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