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If someone wanted to pick up a mil-surplus rifle, or a new rifle, chambered for 7.62X51mm Nato would they also be able to shoot .308 Winchester out of it safely?

Are there any reasons why .308 Winchester Ammunition and 7.62x51mm Nato rounds are not compatible in the same gun?

If I buy something like a Springfield M1A or an Armalite AR10A2 will they both properly feed and function with both types of ammo with no problems?
 

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Yikes... NO!!!!!!!!

7.62x51 is loaded lighter than the .308. The reason for this being that the case walls are thicker and the capacity is a bit smaller. On some manufacturers guns, they can't handle the hotter civilian .308 rounds for very long.

The number one gun to kb on this issue is the older Cetme rifles.

If you find a gun marked .308, it'll handle 7.62x51 but it doesn't work the other way around... You can do it but it isn't safe.

Mike
 

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Magnum88C said:
Yes, any gun chambered for 7.62x51mm will shoot .308.
The opposite isn't always true. The 7.62x51mm has a bit more of an open tolerance, and I believe the length of the cartridge can be longer than the .308 and still be in spec. But the only times I've heard of problems were in guns chambered for .308 that had very tight match chambers.
You are right on about the chamber dimensions. The reason it's dangerous is that match chambers are sometimes not throated enough to allow for the slop in the brass from military rounds. This can cause a pinching effect and lead to an over pressure situation. But never, ever shoot civilian .308 in a 7.62x51 marked barrel.

Mike
 

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I second the thanks. Now I'll have to see how my barrels are caliber marked.

RIKA
 

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Garand, thank you so much for listing the 303 Brit site. I bookmarked it for future reference.

RIKA :)
 

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In reference to the pressure problem, it's interesting that the same problem occurs with .223 vs. 5.56mm but it's the exact opposite.

Mike
 

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Dang, all this metric vs standard system crap really aggravates me. This is why I stick with the all-American cartridges, like the '06 and .35 Rem, more powerful, too. :nyah:
 

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Well now this has gotten me REALLY confused. I am looking at ads for the Russian Vepr that list it as being for .223. Did the Russians REALLY manufacture this military weapon for a civilian cartridge?

Same thing with the Galil, in both .223 and .308. Probably MANY other military style firearms as well....

And most certainly all of the AR-15 variants I see are listed in civilian calibers.

What gives?
 

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The AR's are usually okay. They are over built anyway. There are a few semi's and a few bolt guns that are not safe but they are somewhat rare. Some guns are marked .223 but can handle any 5.56mm... mainly the Remingtons and such.

Mike
 

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5.56 chambering definitely handles hotter loads than

the 223 SAAMI spec chambers. I suspect a similar situtiation exists for 308 and its military designation, but since I'd never bother to own one of those pos's, I've never bothered to really check it out.
 

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5.56mm vs .223



http://www.ammo-oracle.com/body.htm#mk262

Q. What is the difference between 5.56×45mm and .223 Remington ammo?
In the 1950's, the US military adopted the metric system of measurement and uses metric measurements to describe ammo. However, the US commercial ammo market typically used the English "caliber" measurements when describing ammo. "Caliber" is a shorthand way of saying "hundredths (or thousandths) of an inch." For example, a fifty caliber projectile is approximately fifty one-hundredths (.50) of an inch and a 357 caliber projectile is approximately three-hundred and fifty-seven thousandths (.357) of an inch. Dimensionally, 5.56 and .223 ammo are identical, though military 5.56 ammo is typically loaded to higher pressures and velocities than commercial ammo and may, in guns with extremely tight "match" .223 chambers, be unsafe to fire.

The chambers for .223 and 5.56 weapons are not the same either. Though the AR15 design provides an extremely strong action, high pressure signs on the brass and primers, extraction failures and cycling problems may be seen when firing hot 5.56 ammo in .223-chambered rifles. Military M16s and AR15s from Colt, Bushmaster, FN, DPMS, and some others, have the M16-spec chamber and should have no trouble firing hot 5.56 ammunition.

Military M16s have slightly more headspace and have a longer throat area, compared to the SAAMI .223 chamber spec, which was originally designed for bolt-action rifles. Commercial SAAMI-specification .223 chambers have a much shorter throat or leade and less freebore than the military chamber. Shooting 5.56 Mil-Spec ammo in a SAAMI-specification chamber can increase pressure dramatically, up to an additional 15,000 psi or more.

The military chamber is often referred to as a "5.56 NATO" chamber, as that is what is usually stamped on military barrels. Some commercial AR manufacturers use the tighter ".223" (i.e., SAAMI-spec and often labeled ".223" or ".223 Remington") chamber, which provides for increased accuracy but, in self-loading rifles, less cycling reliability, especially with hot-loaded military ammo. A few AR manufacturers use an in-between chamber spec, such as the Wylde chamber. Many mis-mark their barrels too, which further complicates things. You can generally tell what sort of chamber you are dealing with by the markings, if any, on the barrel, but always check with the manufacturer to be sure.
 

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Heck, you can't get more military than a FN-FAL, but look at the photos in this ad placed by Dthomas in this thread: FN-FAL for sale

Do you think this will safely handle 7.62x51 AND .308 ammo? What does the "match" designation mean in this context?
 

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Discussion Starter · #16 ·
Seems to be some confusion over this one. I also found, during my own search, the link that Garand gave to that .303 site. If I read it right, just about any recent firearm chambered for .308 Win should be able to also handle the nato stuff, but not all firearms chambered for the Nato stuff can handle the 308 because it may exapand to much in the larger chamber and due to a thinner case. Did I get that right?
 

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Well what about reloading? The dies I have are small base .308 dies. And I have fired a BUNCH of those rounds through my military style .308 rifles, as well as the few bolt actions I have. Has anyone ever seen a resizing die specifically for the 7.62x51? Heck, if I remember correctly back to when I got the .308 die set, the recommendation for firing .308s in semi auto military style rifles was to use the small base sizer die.

I know I have fired both Hirtenberger 7.62x51 and Black Hills .308 in my Savage .308 with no problems. The Black Hills was MUCH better than the Hirtenberger, for certain. The Hirtenberger didn't produce a "group", it produced a "pattern".
 
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