Dale Posted February 18, 2015 Report Share Posted February 18, 2015 I've been around for more then a little while and always thought 308/7.62X51 was one and the same round... recently, in the last year or so I've been seeing them being referred to as 2 different rounds... I asked my lgs about this and he looked at me like I had 3 eyes... I remember when I went into the Corps that we were told the linked M-60 ammo was loaded a bit hotter but could be shot in the M-14's if necessary... hell if I had 60 ammo and a gun, I sure wasn't gonna unlink it and shoot it outta a 14... I know 223 and 5.56 are basically the same case but the 5.56 is loaded to higher pressures, is this the same as the 30 cal rounds and I've been living in a cave?... or have people been talking out their butts?... Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted February 18, 2015 Report Share Posted February 18, 2015 I've been around for more then a little while and always thought 308/7.62X51 was one and the same round... recently, in the last year or so I've been seeing them being referred to as 2 different rounds... I asked my lgs about this and he looked at me like I had 3 eyes... I remember when I went into the Corps that we were told the linked M-60 ammo was loaded a bit hotter but could be shot in the M-14's if necessary... hell if I had 60 ammo and a gun, I sure wasn't gonna unlink it and shoot it outta a 14... I know 223 and 5.56 are basically the same case but the 5.56 is loaded to higher pressures, is this the same as the 30 cal rounds and I've been living in a cave?... or have people been talking out their butts?... As far as the outside dimensions of the case, they are practically the same. However, the 7.62 NATO round has a thicker case specification and is designed for higher pressure. With the metals most barrels are manufactured from these days, you should have no trouble using them interchangeably. Quote Link to comment Share on other sites More sharing options...
planeflyer21 Posted February 18, 2015 Report Share Posted February 18, 2015 As far as the outside dimensions of the case, they are practically the same. However, the 7.62 NATO round has a thicker case specification and is designed for higher pressure. With the metals most barrels are manufactured from these days, you should have no trouble using them interchangeably. You have that backwards Matt. The .308 Win is the higher pressure round, which is why people were kaBOOMing the surplus Spanish CETMEs a few years back. The 7.62x51 allows for a longer overall cartridge length too. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted February 18, 2015 Report Share Posted February 18, 2015 Cartridge dimensions are the same ( US made ammo ), its the chambers that are a little different , with the 7.62 x 51 having a slightly longer lead to rifling & a small difference in shoulder to neck angle dimensions . All to make the chamber for a battle rifle to be a little looser for battle field conditions & NATO ammo variances . What's the Difference between .308 Winchester & 7.62x51mm NATO? by Clint McKee and Walt Kuleck dumb question i alway thought these 2 ammos where interchangeable but some have told me otherwise whats the story??? jim Hi, Jim, This is a perennial topic, kinda like ".45 vs. 9mm" or "Best Guns & Loads for Deer." They are not the same. They are the same. They are not the same, 'cause the .308 Win was released by Winchester several years before the Army standarized the T64E3 as the 7.62MM. You'll get an endless discussion of pressure specs, endless because SAAMI and the Ordnance Dep't measured pressure in different, unrelateable ways. Howver, the chamber drawings are different. They are the same, 'cause nobody (and Clint's been looking for many years!) makes 7.62MM ammo that isn't to the .308 "headspace" dimension spec. So 7.62MM ammo fits nicely into .308 chambers, as a rule. But in some 7.62MM rifles the chambers are long (to the 7.62MM military spec), notably the Navy Garands with 7.62MM barrels. Thus, using commercial ammo in such a rifle is not a good idea; you need stronger brass. Use military ammo or the best commercial only, e.g., Federal Gold Medal Match. Most of the time it's a distinction without a difference. But if you intend to shoot .308 commercial in a military arm chambered for 7.62MM, first check the headspace with .308 commercial gauges first. You may get a surprise. Best regards, Walt KuleckFulton Armory webmaster Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted February 18, 2015 Report Share Posted February 18, 2015 You have that backwards Matt. The .308 Win is the higher pressure round, which is why people were kaBOOMing the surplus Spanish CETMEs a few years back. The 7.62x51 allows for a longer overall cartridge length too. You're right, I had it bass ackwards... apologies to the OP. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted February 18, 2015 Report Share Posted February 18, 2015 ^^^ Just on the pressure differences (which are measure with two completely different methods). You nailed it on the case thicknesses - 7.62x51 cases are thicker through the walls, and have more thickness in the webbing at the bottom, around the primer. Somewhere around here I posted a pic of the two cases going lengthwise through the chopsaw. Quote Link to comment Share on other sites More sharing options...
shepp Posted February 18, 2015 Report Share Posted February 18, 2015 ^^^ Just on the pressure differences (which are measure with two completely different methods). You nailed it on the case thicknesses - 7.62x51 cases are thicker through the walls, and have more thickness in the webbing at the bottom, around the primer. Somewhere around here I posted a pic of the two cases going lengthwise through the chopsaw. I know there are a few pretty extensive topics on this in the ammo section...... Quote Link to comment Share on other sites More sharing options...
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