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It is or isn't?
Waco Waltz
Member Posts: 10,828 ✭✭
Says it's .308 and 7.62x39
You need to link over the corect video. This one was the same as you are using over in GD in a totaly unrealted topic.
I thought there was a difference and that you don't want to shoot the 308 in military spec rifles or the 7.62 in civilian hunting rifles?
What's the real story?
You need to link over the corect video. This one was the same as you are using over in GD in a totaly unrealted topic.
I thought there was a difference and that you don't want to shoot the 308 in military spec rifles or the 7.62 in civilian hunting rifles?
What's the real story?
Comments
7.62x39 is the Russian round for the SKS and AK-47 type rifles.
While the nominal bullet size is the same (it really isn't at .308 VS .311) the case length is totally different
"".308 Win vs. 7.62x51--The Straight Scoop
Before we go much further, lets address the oft-posed question "Are the .308 Winchester and 7.62x51 NATO one and the same?" The simple answer is no. There are differences in chamber specs and maximum pressures. The SAMMI/CIP maximum pressure for the .308 Win cartridge is 62,000 psi, while the 7.62x51 max is 50,000 psi. Also, the headspace is slightly different. The .308 Win "Go Gauge" is 1.630" vs. 1.635" for the 7.62x51. The .308's "No-Go" dimension is 1.634" vs. 1.6405" for a 7.62x51 "No Go" gauge. That said, it is normally fine to shoot quality 7.62x51 NATO ammo in a gun chambered for the .308 Winchester (though not all NATO ammo is identical). Clint McKee of Fulton Armory notes: "[N]obody makes 7.62mm (NATO) ammo that isn't to the .308 'headspace' dimension spec. So 7.62mm ammo fits nicely into .308 chambers, as a rule." You CAN encounter problems going the other way, however. A commercial .308 Win round can exceed the max rated pressure for the 7.62x51. So, you should avoid putting full-power .308 Win rounds into military surplus rifles that have been designed for 50,000 psi max..... Reloaders should also note that military ammo often is made with a thicker web. Consequently the case capacity of 7.62x51 brass is usually less than that of commercial .308 brass. You may need to reduce recommended .308 Winchester loads by as much as 2 full grains, if you reload with military 7.62x51 brass, such as Lake City or IMI.""
There is no claim that the bullet size is the same.
7.62mm = .300" which is the nominal bore diameter of all three. (The MN was once known as the Three Line Rifle where a line is 1/10 inch.)
The difference is that the Russians cut deeper rifling grooves than we do and use larger bullets to seal the barrel.
7.62x51 NATO is a 50,000 psi cartridge
Well, sort of. Thing is, the specifications were set over 50 years ago when crusher gauges calibrated in pounds per square inch by hydraulic or dead load methods were standard. When piezoelectric transducers came into use, SAAMI started calling the reading "psi" and crusher gauge readings Copper Units of Pressure (CUP.)
Confusion arises because the US Army is not a member of SAAMI and does not use the CUP term. They called crusher gauge readings psi for a long time, giving rise to the Urban Legend that 7.62 is a substantially lower pressure round than .308 Win. Actually it is a SLIGHTLY lower pressure round, 50,000 (same as .30-06) vs 52,000 for .308 (close to .270) when measured by the same method.
Military chambers are somewhat larger in diameter and headspace dimensions because automatic weapons will be shot hot and dirty.
Also with ammunition of variable size and quality obtained from allies who may not stick as close to spec as we do.
The main source of trouble I see here is shooting .308 in a 7.62 chamber and resizing it heavily in reloading, leading to brass failure. Gauging and chamber checking will help, as will not using brass as many cycles in your battle rifle as in your hunting rifle.
Says it's .308 and 7.62x39
You need to link over the corect video. This one was the same as you are using over in GD in a totaly unrealted topic.
I thought there was a difference and that you don't want to shoot the 308 in military spec rifles or the 7.62 in civilian hunting rifles?
What's the real story?
Its hard to understand your question, but I see two here:
a. 7.62x39 is a cone shaped low power short range cartridge used in the original Kalashnikov pattern rifles (eg AK-47), and SKS carbines.
This round is totally dimensionally different than 7.62x51 NATO or .308 Winchester and without a specialized chamber adapter, this round CANNOT be fired in those other guns. Likewise, its totally impossible to fire a .308 or 7.62x51 in a gun chambered for 7.62x39, the longer .308 rounds are simply too big to fit in the smaller 7.62x39 chamber.
b. On 7.62x51 NATO vs .308 Winchester, the detailed answer has been given above. To make a long story short, the cartridges are highly similar but not entirely identical; the civilian .308 Winchester "may" be loaded *slightly* hotter, and there are slight differences in spec of the brass, mostly just thicker brass on the military cartridges to limit case stretching.
The most significant difference from a shooting perspective, isn't the difference in the BRASS, its the difference in the CHAMBERS. The military guns have slightly looser chambers to allow dirty ammo to run better, and to provide buffer against ammo from a variety of sources that may be slightly out of spec. The looser chambers will result in more wear and tear to .308 brass fired through military guns, but that's a separate issue/question.
In short, you can safely fire all the military issue/surplus 7.62x51 NATO spec ammo you like through a conventional civilian .308 Winchester rifle.
While the converse is sometimes NOT advised, because of the slightly increased max pressure of .308 ammo, my understanding is that most commercial .308 is simply NOT loaded to its maximum pressure potential. Furthermore, pretty much every modern 7.62x51 NATO gun is quite a bit stronger than the NATO max pressure standard, to the point where a possible *slight* difference in pressure with civilian .308 ammo won't make a difference.
In short, you're simply not going to "blow up" an AR-10 or any similar current production rifle using .308 ammo, no matter how much you use.
If you're using some ancient marginal bolt-gun gun converted to 7.62 NATO from something else, then you may want to limit high pressure ammo (.308 or other), because it can deform lugs and alter headspace, and like over time.
How is this so?
I don't know where the link went it was an ammo retailer and simply stated they had a brand or two that stated the ammo was both .308 and 7.62x51 at the same time.
How is this so?
I don't think it can truly be both, since the specs of the two are a little bit different.
The ammo makers probably mean that these aren't loaded to max .308 max pressures and should be safe in either 7.62x51 or .308 guns. That's the only explanation that makes sense.
If you really want to know, you'll have to find the link and then ask the manufacturers.
What they might be saying is it is 308 diamter bullets LOADED in 7.62x39 cases.
As was earlier posed; the original bullets for this round were .311 diameter...and some guns have .311 bores. While others (usually American-made modern guns) have .308 bores.
I don't think it matters whether you load those with commercial or military ammo. The ones I know of were converted for ammunition compatibility with current weapons, but for issue to people who were not going to be doing a lot of shooting. Border guards and line of communication troops, for example. The American Plinker, proud of burning ammo by the case, might not find them as durable as he would like.
quote:and some guns have .311 bores. While others (usually American-made modern guns) have .308 bores.
No.
They have .300" bores. Their groove diameters are .308" or .311", depending on maker. Or larger, the European gunmaker thinks the groove diameter can reasonably be larger than bullet diameter to give the metal displaced by the rifling someplace to go. Us Yanks don't.
are the same.