.308 in a 7.62 nato gun


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Soybomb
October 6, 2007, 03:12 AM
So I've got an enfield 2a in 7.62 nato coming. I've always been told and read not to fire .308 in guns chambered for nato. I just saw this article http://www.surplusrifle.com/shooting2006/308vs762nato3/index.asp though and it has me thinking with some rounds it might not be so bad...plus the left over brass should be reloadable for me in the future unlike most surplus stuff. It all seems to make sense to me. What do you guys think? Does it look sound or look like a way to wind up with enfield face?

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AndyC
October 6, 2007, 08:55 AM
This is always an annoying question because there is no definitive answer - it depends. The basic issue is that you're wanting to shoot a generally higher-pressure cartridge (308) which has a thinner case in a longer-than-normal chamber (7.62).

It's usually quite safe to shoot 7.62 in a .308, but not necessarily the other way around - it depends on the specifics of the components used (stacking of tolerances). Measure your 7.62's headspace with .308 Win headspace gauges; if it's good to go, you're good to go if you have decent .308 ammo.

I would suggest you do some reading on this subject first, though - what works for one person's rifle will not necessarily work for another. Excessive headspace, thinner-walled cases and higher pressures stacking up on each other are not a pleasant thought when it happens just in front of your eyeball.

TexasRifleman
October 6, 2007, 10:08 AM
There are several threads on this, and I've posted a lot on this subject. Here is what Clint McKee has to say about it, and it covers it pretty well I think. Ignore the M14 stuff but note the headspace dimensions. It's always recommended to headspace your weapon and make your decision based off your individual chamber dimension.

Best thing to do is check the headspace of a 7.62 weapon with .308 headspace gauges and see. It can vary widely from weapon to weapon even from the same manufacturer given the use and abuse most surplus weapons have seen.

Jerry Kuhnhausen, in his classic Shop Manual (available from Fulton Armory; see the M1 Rifle Parts & Accessories or M14 Rifle Parts and Accessories Pages under Books) has published a somewhat controversial recommendation concerning .308 Winchester and 7.62x51mm NATO ammo, headspace & chambers. I broached the subject with him some months ago. He had his plate full, so we decided to chat on this in the future. When we do I'll report the results of our conversation.

I completely agree with Jerry that if you have a chamber with headspace much in excess of 1.636 (say, 1.638, SAAMI field reject), you must use only U.S. or NATO Mil Spec Ammo (always marked 7.62mm & with a cross enclosed by a circle) since the NATO mil spec calls for a far more "robust" brass case than often found in commercial (read .308 Winchester) cartridges. It is precisely why Lake City brass is so highly sought. Lake City brass is Nato spec and reloadable (most NATO is not reloadable, rather it is Berdan primed). Indeed, cheaper commercial ammo can fail at the 1.638 headspace (e.g., UMC) in an M14/M1 Garand. Many military gas guns (e.g., M14 Rifles & M60 Machine guns) run wildly long headspace by commercial (SAAMI) standards (U.S. Military field reject limit for the M60 & M14 is 1.6455, nearly 16 thousandths beyond commercial (SAAMI) GO, & nearly 8 thousandths beyond commercial (SAAMI) field reject limit!).

stubbicatt
October 6, 2007, 10:51 AM
Years ago when those 308 Enfields were first available, there was a spate of issues with case head separations because the headspace was quite off on them. Before you shoot that thing, be sure a gunsmith checks your headspace.

With the rimmed 303 round you could change bolt heads to get headpace right, as it headspaced on the rim. With the NATO round, changing bolt heads might not accomplish anything if the chamber is cut too deeply.

Deer Hunter
October 6, 2007, 03:03 PM
Don't know if it makes any difference, but I've shot winchester 150 grain powerpoint from my Ishy enfield with no problems whatsoever.

Soybomb
October 23, 2007, 06:35 PM
Sounds like I should get some .308 headspace gauges. Any cheaper place than brownells to get them?

I thought it was as simple as a pressure difference but I guess I should have known better seeing that the velocity between the 2 rounds with very similar weighted bullets is nearly identical.

TexasRifleman
October 23, 2007, 06:40 PM
Any cheaper place than brownells to get them?

Might be cheaper to have a local gunsmith check it for you rather than buy all the stuff to do it yourself unless you just want to.

I think I paid a guy $25 to check a chamber for me last year.

Soybomb
October 24, 2007, 06:14 AM
Probably the better deal with 1 rifle, but it looks like for 2 rifles at prices like that you're probably just as well to order the gauge or you'd even save some money with a c&r discount.

Bwana John
October 24, 2007, 01:50 PM
Most headspace gauges are .308 GO/NO GO, this will not help you.:cuss:

Get a .308 FIELD gauge(1.638), Ill bet that Indian will swallow a NO-GO (1.634).;)

If it will close on a .308 FIELD guage dont shoot .308, get a 7.62 FIELD gauge, if it will close on that dont shoot the rifle.

fatelk
October 24, 2007, 03:08 PM
This is the mosts informative thread on the 7.62 vs 308 controversy I've read so far. Thanks for the great info! I have two 2A rifles.

I've read a lot of places where people say 308 is "hotter" than 7.62, then I read two or three articles by guys who claim to know for a fact that that is not so. Finally it makes sense that it is a headspace and brass thickness issue.

I do not have a headspace guage, but I do have some old Syrian ammo that will not chamber easily in my Rem 700. It chambers very hard in the one 2A, but goes in quite easily in the other one. It looks like that second one does not get any commercial 308.

kennedy
October 24, 2007, 04:30 PM
I have a Rem 700 in .308, and from what I have read in this thread it is ok to shoot 7.62 nato, correct? anyone have any great results in the accuracy of a peticular 7.62 round I should look at buying?

Soybomb
October 24, 2007, 06:14 PM
Thanks Bwana, saved me some bucks there! Looks like $17 for a .308 field gauge, I'll have to dig around a little more to find a nato one. Still sounds like a good idea to be safe when in doubt.

I also noticed that winchester's whitebox .308 is labeled .308 and 7.62 Nato. I emailed them to get the story behind that was told:

Thank you very much for taking the time to contact us here at Winchester
Ammunition. We are always glad to hear from our many friends and customers
who share in the shooting sport.

As long as your rifle is a 7.62 and the ammunition reads 7.62 it would be
safe to shoot in your rifle.

Thank you again for contacting us here at Winchester Ammunition. If you
should require additional information, do not hesitate to contact us.

Sincerely,

Winchester Technical Department

So not having any in front of me I'd be curious to hear from those that have shot the winchester stuff, are they loading into .308 brass or nato brass?

TexasRifleman
October 24, 2007, 07:27 PM
anyone have any great results in the accuracy of a peticular 7.62 round I should look at buying?

Most of it is gonna be surplus and the accuracy is not going to be as good as a Match grade commercial .308.

The South African shoots pretty well for me, as does Lake City if you can find any. Pakistani is 100% reliable and clean but accuracy sucks.

silverlance
October 25, 2007, 04:37 AM
308 is 60,000 cups
7.62 is 50,000 cups

my handloaded 308 for my ishy is 48,000 cups.

USSR
October 25, 2007, 12:43 PM
308 is 60,000 cups
7.62 is 50,000 cups


Nope. .308 is 62,000 psi, 7.62 is 50,000 CUP. Totally different methods of measurement.

Don

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