7.62 NATO or .308 Winchester


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jwc7
May 2, 2012, 03:25 PM
I'm looking to purchase a 7.62 NATO or .308 Winchester on an AR type platform. Anyone have any opinions on which caliber they prefer and/or any suggestions on a manufacturer that builds a reliable and reasonably inexpensive rifle?

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allaroundhunter
May 2, 2012, 03:26 PM
They are the same caliber.....

I have only fired a Rock River Arms .308 AR, but it was very nice and is on my list of guns to get.

jwc7
May 2, 2012, 03:31 PM
Not really the same caliber. Been doing some research on the two and I find that not only are the brass walls different, but the .308 can go up to 62,000 psi while the NATO is limited to 50,000 psi. GENERALLY speaking, it is ok to fire the NATO in a .308 but not the other way around.

Scimmia
May 2, 2012, 03:40 PM
Old wives tale. NATO isn't limited to 50K PSI, it's limited to 50K CUP, which is a totally different system of measurement. The chambering may be different, but pressure is NOT the reason.

jwc7
May 2, 2012, 03:41 PM
OK, enlighten me! I'm only going by what I've read so far.

ol' scratch
May 2, 2012, 03:44 PM
Talk about a can of worms. The reason for the differences in PSI is the way the Europeans and the Americans measured it. There is a difference in the chamber dimensions when comparing the two. The 7.62 NATO chambers are slightly longer. The rounds are demenionally the same, but as mentioned there is a difference in internal case dimensions from the heavier construction. My concern (and it may be unfounded) is excessive case stretch and possible thinning of brass if you reload the commercial brass for a 7.62 NATO rifle due to the longer chamber. The 7.62 NATO spec brass is thicker, so I view it as less of a problem.

Rapidrob
May 2, 2012, 03:44 PM
I fired my first 7.62x51 rifle in 1957. Since then I have shot thousands of rounds of .308 out of 7.62x51 NATO chambered with never a problem. I don't use a heavier bullet than what is used for combat of long range matches. Not for a blowing -up problem, but gas port pressures being too high.

allaroundhunter
May 2, 2012, 03:47 PM
Old wives tale. NATO isn't limited to 50K PSI, it's limited to 50K CUP, which is a totally different system of measurement. The chambering may be different, but pressure is NOT the reason.

Yup, here it is. The only possible problem is for reloaders using .308 Win brass out of a 7.62x51 mm rifle due to a slightly longer NATO chamber.

ol' scratch
May 2, 2012, 03:49 PM
What do you consider inexpensive?

jwc7
May 2, 2012, 03:56 PM
So...if I understand everyone correctly, if I do not reload, and I use only commercially available cartridges, I should be good going either way; .308 in NATO chamber and NATO in .308 chamber.

For ol'scratch: I would love to stay under $1,500 if possible.

allaroundhunter
May 2, 2012, 04:00 PM
So...if I understand everyone correctly, if I do not reload, and I use only commercially available cartridges, I should be good going either way; .308 in NATO chamber and NATO in .308 chamber.

For ol'scratch: I would love to stay under $1,500 if possible

Yes. And does that price point include an optic? Or just the rifle?

ol' scratch
May 2, 2012, 04:06 PM
If $1500 is just the rifle, I would say AR-10 due to the larger number of accessories and SOME interchangablity with the AR-15

jwc7
May 2, 2012, 04:11 PM
Just the rifle, I have some really good optics already.

allaroundhunter
May 2, 2012, 04:17 PM
Just the rifle, I have some really good optics already.

The AR-10 has a good reputation, but I have no experience with it. I will also recommend an RRA LAR-8 Predator or Varmint.

splithoof
May 2, 2012, 04:25 PM
I have been using quite an amount of .308 & 7.62X51mm ammunition in a good variety of rifles to include military pattern, hunting, target shooting, and a few single-shot pistols. I started been doing this since 1984, and have mixed ammunition from many different makers, reloaded the brass from most of it, and NEVER had any problems. Granted that I size and trim everything to a same uniform length, and care for primer pockets, for all practical purposes I see no difference. If you want absolute accuracy, yes you can separate cases my manufacturer and weight. To my experience the headstamp markings mean nothing when all is said and done.

brnmuenchow
May 2, 2012, 05:12 PM
They are not exactly the same true, but close enough to where either one can be fired from a .308 Win. chambered rifle with no issues.

Enachos
May 2, 2012, 06:23 PM
+1 For the RRA LAR-8. Excellent rifle!

HankB
May 2, 2012, 07:55 PM
Headspace is slightly different for the two rounds.

308 Win “Go" gage is 1.630″
7.62x51 "Go" gage is 1.635″

308 Win “No-Go” gage is 1.634″
7.62x51 "No-Go" gage is 1.6405″

More info here: http://www.fulton-armory.com/faqs/M14-FAQs/308.htm

DesertFox
May 2, 2012, 08:11 PM
M1A1, M14, Winchester SX-AR (FN-AR in Mossy Oak Brush pajamas) and Remington R-25 (DPMS AR-10 in Mossy Oak Treestand pajamas) here. Other ones I've seen that I'd like to try are the Sig, the FN SCAR 17, the HK and the Colt. All of those but the Sig have rather hair-ball sized price tags.

Of those that are lying around here, they all have their strong points, they all have their quirks and they are all HEAVY. Specially with good glass. I like the looks of that Sig but have seen lots of comments regarding QC issues with Sig. I'd try to fondle them all to see which one talks to you.

Oops... Almost forgot ye ole FAL. Prolly my favorite in 7.62x51. HK91 is good too but that lack of last shot hold open on empty mag is kind of a deal breaker.

35 Whelen
May 2, 2012, 10:04 PM
I'm looking to purchase a 7.62 NATO or .398 Winchester on an AR type platform. Anyone have any opinions on which caliber they prefer and/or any suggestions on a manufacturer that builds a reliable and reasonably inexpensive rifle?
A buddy of mine bought DPMS AR10 type rifle in 6.5 Creedmoor fpr both High Power and hog hunting. That is one heavy beast. Super quality rifle though and very, very accurate routinely grouping around 1/2" (scoped) at 100 yds with Hornady factory ammo.
I'm sure their .308's would be just as accurate.

35W

nyc71
May 2, 2012, 10:55 PM
how many times yall got to talk about this. redundant question.

I'm not picking an argument but if you has no interest in the topic then you should not participate. let's stay positive towards one another, we have enough gun haters to deal with as it is.

35 Whelen
May 2, 2012, 11:01 PM
I'm not picking an argument but if you has no interest in the topic then you should not participate. let's stay positive towards one another, we have enough gun haters to deal with as it is.
Exactly. The OP obviously is new to the forum, so let him ask!

35W

303tom
May 3, 2012, 10:03 AM
The .308 Winchester & the 7.62x51 NATO are one in the same.............

http://en.wikipedia.org/wiki/.308_Winchester

http://en.wikipedia.org/wiki/7.62x51mm_NATO

jonnyc
May 3, 2012, 10:12 AM
Just to clarify a few postings:
1. Yes, both are essentially the same round with 2 names.
2. 7.62 Nato chambers are a bit more generous than commercial .308 chambers.
3. Factory loads are completely interchangeable.
4. Military brass is generally thicker near the base to withstand violent MG extraction, so its internal case is a little less than commercial brass. This is an issue for those reloaders who use hot .308 loads.

jwc7
May 3, 2012, 10:17 AM
I looked at the two references you had in your response and, while small, there are differences, although it seems that they can be fired almost interchangeably.

jonnyc
May 3, 2012, 07:49 PM
No, .308 was simply the commercial Winchester name for the military-developed 7.62x51 cartridge. That's it. Military and commercial chambers are manufactured to different specs, not the ammunition.

Robert101
May 3, 2012, 08:17 PM
It seems to me that the ammo is made slightly different and here is why. My RCBS dies full length resize 308 brass easier than NATO brass. I'm not saying it is very much but the press handle goes down a lot harder on NATO brass. I know the NATO brass is thicker. In my DPMS 7.62X51MM NATO barrel I get away with a slight space between the shell holder and the bottom of the die (.015). This setting still allows the ammo to work well and minimizes the expansion and resizing of the brass.

303tom
May 3, 2012, 10:05 PM
No, .308 was simply the commercial Winchester name for the military-developed 7.62x51 cartridge. That's it. Military and commercial chambers are manufactured to different specs, not the ammunition.
The other way around, Winchester developed the round for commercial use before they sold it to the military.

ball3006
May 3, 2012, 10:11 PM
If you guys would read any reloading manual, the topic of reloading military brass is discussed and advice given. Reloading manuals have said this for the last 55 years I have been reloading........chris3

bergmen
May 3, 2012, 10:12 PM
Headspace is slightly different for the two rounds.

308 Win “Go" gage is 1.630″
7.62x51 "Go" gage is 1.635″

308 Win “No-Go” gage is 1.634″
7.62x51 "No-Go" gage is 1.6405″

More info here: http://www.fulton-armory.com/faqs/M14-FAQs/308.htm

My copy of SAAMI specifications lists 1.640 Max / 1.630 Min for .308 Winchester chamber headspace specifications.

I would post the page but reproduction is prohibited by copyright.

Dan

wristtwister
May 3, 2012, 10:29 PM
The slightly longer case length of the 7.62 X 51 is not a problem in the .308 rifles, but the .308's in the NATO chambers sometimes split the cases when fired, as the brass expands to fit the chamber. It's not something that necessarily happens every time, but it does make you take time to measure and cut your cases to length on "once fired" brass. I won't venture a guess how it acts in an AR profile rifle, but in a bolt gun, this is pretty much the rule. Once you fire a .308 in a NATO chambered rifle, you need to both do case trimming and measuring your cases before and after reloading.

I've shot a ton of both in my .308 bolt guns, and had no problems. I have, however, learned that I have to really do a good job of cleaning out the primer pockets and making sure the neck sizing is correct on the NATO rounds. They have a "military crimp" that has to be removed when sizing, and if you're properly seating your bullets, you have to make sure your cases have been properly cut. If I remember correctly the cases are about .13" different, which accounts for the case expansion of the .308's.

Sorry, but I don't have my reloading book nearby, or I'd give you exact numbers, but it isn't hard to do the math... and suffice it to say the longer cartridge throat measurement is what drives this argument (the NATO cartridge throat).

WT

NWCP
May 4, 2012, 05:54 AM
Get your rifle chambered in .308 and don't worry about it.

303tom
May 4, 2012, 08:38 AM
http://www.saami.org/specifications_and_information/index.cfm

Carl N. Brown
May 4, 2012, 09:37 AM
My son has a .308 Win caliber Savage Tactical, a 7.62x51 FAL on a Imbel receiver and what turned out to be a 7.62x51 HK built on a Hesse receiver (I thought it was a CETME but I was wrong.). Over the years I have heard all the stories about how compatible/NOT the two cartridges are supposed to be. I am not sure what to believe.

The case of both 7.62x51mm NATO and .308 Winchester is rimless, bottleneck, center fire.
The .308 Win was developed from the .300 Savage which was designed to duplicate .30-06 ballistics within the action length of the Savage 1899 leveraction rifle.
The 7.62x51mm NATO was developed from the .308 Win.


Cartridge specifications posted at Wikipedia
7.62x51mm NATO .308 Winchester
Bullet diameter 7.82 mm (0.308 in) 0.308 in (7.8 mm)
Neck diameter 8.77 mm (0.345 in) 0.3433 in (8.72 mm)
Shoulder diameter 11.53 mm (0.454 in) 0.4539 in (11.53 mm)
Base diameter 11.94 mm (0.470 in) 0.4709 in (11.96 mm)
Rim diameter 12.01 mm (0.473 in) 0.4728 in (12.01 mm)
Rim thickness 1.27 mm (0.050 in) 0.0539 in (1.37 mm)
Case length 51.18 mm (2.015 in) 2.015 in (51.18 mm)
Overall length 69.85 mm (2.750 in) 2.800 in (71.12 mm)
Case capacity 56 gr H2O (3.64 cm2)
Maximum pressure 415 MPa (60,200 psi) 62,000 psi (430 MPa)
data sourced to data sourced to
Popenker RU.guns Federal Cartridge Co.

I think Overall length has more to do with bullet selection than
any characteristic of the cartridge.

I suspect the case capacity of the 7.62x51mm is less as military
brass tends to be more robust since military guns are rougher on
ammo than civilian actions.

A previous thread on the subject: http://www.thehighroad.org/archive/index.php/t-318489.html&amp&

Sourced to QuickLoad:
.308 Win (Commercial) 56.00 grains of water,
7.62x51mm NATO (Military) 52.00 grains of water

One poster measured his 7.62x51mm from Lake City arsenal as between 54.5gr and 55.0gr of H2O.

I gather the rule should be don't mix brass from different makers or
even different lots from the same maker. Don't expect to get
consistent results if you use the same load in mixed brass.

jwc7
May 4, 2012, 09:42 AM
Boy, did I start a firestorm or what!

I guess the answer is more complicated than I originally thought. Anyway, I am going to take the advice of member NWCP, buy a .308, and don't worry about it.

Thanks to everybody!!!!!!!

ExAgoradzo
May 4, 2012, 10:05 AM
+1 @JWC7 that's my takeaway from this discussion too! I did really appreciate the education though guys!

Robert
May 4, 2012, 11:00 AM
Since this has been asked and answered and the OP is happy we are going to end on a high note. Thanks to all the members that aided in the education of a new member.

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