.308 Win VS. 7.62x51mm NATO

[BenMara]

.308 Win VS. 7.62x51mm NATO

saw in another thread there are more differences then what i see

I want o hear your info

 

[Dave29461]

This is from AmmoGuide http://ammoguide.com If you reload it is a good resource. Costs 18.95/yr and is worth it.

The original cartridge was developed by the Ordnance Dept. of the U.S. Army in the 1940's through 50's under the name T-65. After extensive testing, it was to become the first NATO-adopted "standard" cartridge, the 7.62mm NATO, or 7.62x51mm.

Winchester requested and received permission to introduce the cartridge commercially as the .308 Winchester. The result has been worldwide acceptance in a range of sporting firearms. However, the 7.62x51mm NATO and .308 Winchester should not be considered interchangeable. More on that below.

The military endeavor was to improve upon the .30-06 Springfield round, which had been in service since 1906 (or 1903 if one considers it's real origin as the .30-03). The result was a round of substantially less weight and size, while retaining the same bore diameter as well as only a negligible drop in ballistics (muzzle velocity was within 100 fps of the larger round).

The .308 has been neck-sized successfully to a variety of commercial calibers. These include the .243 Winchester, the 7mm-08 Remington and the .358 Winchester. All are excellent choices for short-action rifles, covering a wide-range of applications.

Key differences exist between military and commercial designs, notably in the hardness and thickness of the brass as well as the external dimensions of the case itself. The shoulder and neck of the military design dictate they are farther from the rim by .013 inches (commercial spec shown above), resulting in a significantly different headspace situation between the two rounds. The combination of shorter commercial ammunition in the slightly longer military chamber presents a possibly dangerous situation due to the emergence of a gap in the mating of case and chamber shoulder surfaces.

Even if military cases are shaped to the commercial chamber, it's reloading characteristics are different from commercial brass. The increased thickness of military brass results in more difficult sizing operations and reduces available powder capacity. This has the effect of increasing pressures when using military cases, with like charges. Also, primer pockets are likely to be crimped, complicating priming and de-priming operations. Nonetheless, some precision target shooters are careful to deal with these issues and prefer military "Match" 7.62x51mm cases, fire-formed to their chamber.

The .308 Winchester family can be viewed here:
http://ammoguide.com/cgi-bin/aicompa...65|388

 

[Schultz]

Here's another link but Dave's nailed it http://www.303british.com/id36.html I learned the hard way when I first got into 7.62x51 Thought I'd save some cash using 308 which didn't go well. :?

 

[bigfutz]

Does anyone have experience shooting 7.62 cartridges in a rifle chambered for .308, my specific interest regarding the DPMS LR-308? The Web is just too full of differing opinions; I thought I would give a more trusted community a try.

 

[Tigerstripe]

all i can say is once my cases are fired and trimmed the difference is thickness. im not looking to reach the moon so all my loads are well below max and work in both cases. i have over 1000 reloads of mixed cases ready and its not their first rodeo.

i use a model 7 Rem bolt
model 700 youth
Armalite AR-10

 

[45Automatic]

I'm new here, and never formally introduced myself. anyway, I shoot 7.62x51 all day out of my .308 remington 700 LTR without issue. just sayin

 

[Dave29461]

You payz yer money and takez your chances. I just try not to jeopardize my life, sight or firearms...or the people standing around when I pull the trigger. I try to stack the deck in my favor. And this is why they call it Personal Freedom.

 

[Tigerstripe]

i just looked and my AR-10 says 7.62 MM

ill bet its 308 though.

 

[BenMara]

Ok I have a very large pile of .308/7.62 other then the stampings, do i need calipers to tell difference between them?

 

[bigfutz]

BenMara, what is your interest or better yet, what is your objective? Do you have a particular rifle marked one way and a pile of mixed ammo? Depending on how big the pile was, I might be inclined to sort it by stamp, then break out the calipers. If you don't have calipers, maybe take one of each sampling to a nearby gunsmith.

And please post your results here. I'm interested as well.

 

[Low Country Five-0]

Does anyone have experience shooting 7.62 cartridges in a rifle chambered for .308, my specific interest regarding the DPMS LR-308? The Web is just too full of differing opinions; I thought I would give a more trusted community a try.

Just picked up a DPMS LR-308. The barrel is stamped 7.62x51 so I think it should be able to handle either one. I haven't had a chance to send lead down range with it yet but I plan on using both .308 and 7.62x51 through it.

 

[BenMara]

I only currently shoot a bolt action 308, ive shot 308 and 7.62 from it, ive separated my brass into 308 and 7.62 piles, according to head stamp. But still have a pile with no designation of 308 or 7.62, but have same dimensions of said brass

 

[Clicker]

I only currently shoot a bolt action 308, ive shot 308 and 7.62 from it, ive separated my brass into 308 and 7.62 piles, according to head stamp. But still have a pile with no designation of 308 or 7.62, but have same dimensions of said brass

If you know which ones were fired in which rifle you could simply neck size them and check OAL (trim if needed) then load & shoot each batch of ammo in their respective rifle again.
Let me know if I can help. You can do the work here or drag the press & trimmer around the corner to your house and play with it.

 

[bigfutz]

Does anyone have experience shooting 7.62 cartridges in a rifle chambered for .308, my specific interest regarding the DPMS LR-308? The Web is just too full of differing opinions; I thought I would give a more trusted community a try.

Just picked up a DPMS LR-308. The barrel is stamped 7.62x51 so I think it should be able to handle either one. I haven't had a chance to send lead down range with it yet but I plan on using both .308 and 7.62x51 through it.

My LR-308 says 308. I think DPMS actually makes two separate chamberings. Mine is the 308 SS bull 24". Which do you have?

DPMS is pretty specific about not using anything but what is marked on the barrel, and they also say shooting steel cased ammo voids the warranty. But, they might be just covering their butt. As for me, I don't think I'm going to chance it. I have found pricing is about the same (low end that is), but there are definitely more varieties available in 308 (hunting, match, etc in 308 vs. mostly milsurp in 7.62). If I had a 7.62 marked barrel, I would dig a little harder.

 

[Low Country Five-0]

My LR-308 says 308. I think DPMS actually makes two separate chamberings. Mine is the 308 SS bull 24". Which do you have?

DPMS is pretty specific about not using anything but what is marked on the barrel, and they also say shooting steel cased ammo voids the warranty. But, they might be just covering their butt. As for me, I don't think I'm going to chance it. I have found pricing is about the same (low end that is), but there are definitely more varieties available in 308 (hunting, match, etc in 308 vs. mostly milsurp in 7.62). If I had a 7.62 marked barrel, I would dig a little harder.

Mine has a 16" barrel with the standard AR type flash hider. It has the "sportical" type upper receiver without the dust cover and forward assist. Last week I picked up a bunch 7.62x51 brass cased milsurp ammo from another forum member. That should be plenty to keep me shooting for a while. All the paperwork that came with the gun says .308 win so I guess its good to go since there are no warnings saying not to use one or the other. Maybe an email to DPMS would help clear up any questions.

 

[Tigerstripe]

i dont get it. lets beat this horse some more.

ive loaded for 40 years. years ago none of the loading manuals made a distinction between 5.56 and 223 or 7.62x51 and 308.

i have bolt 308s and semi AR-10 marked 7.62.

so, which is not supposed to shoot what? i full length size and trim to length.

 

[bigfutz]

Supposedly a 308 in a 7.62 will have a headspace gap, and thus a 7.62 won't seat completely in a tight 308. Or maybe it's just hooey for people to IMO inline.