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Old March 7, 2013, 09:11 PM   #1
Blue1
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7.62 NATO/.308 compatability

Can 7.62 NATO rounds be safely used in a .308 Winchester chamber? Can the .308 Win round be used in a 7.62 NATO chamber?

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Old March 7, 2013, 09:19 PM   #2
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Re: 7.62 NATO/.308 compatability

Yes.
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Old March 7, 2013, 09:35 PM   #3
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Just like .223/5.56, they were both the same before the internet.
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Old March 7, 2013, 09:35 PM   #4
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Usually they are interchangeable: some related links.
http://answers.yahoo.com/question/in...5154413AAqrYDu
http://www.303british.com/id36.html
http://www.ar15.com/forums/t_6_2/377...62.html&page=2
http://how-i-did-it.org/762vs308/chamber.html
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Old March 7, 2013, 10:18 PM   #5
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Old March 8, 2013, 08:00 AM   #6
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Yes.
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Old March 8, 2013, 12:13 PM   #7
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The very first link repeats the myth that 7.62x51 is 50,000PSI It's 50,000 CUP not PSI Quit mixing up units please. Tried of seeing that misinformation repeated over and over again..
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Old March 11, 2013, 06:51 AM   #8
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Yes, but why would you want to shoot FMJ thru your fine hunting rifle?
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Old March 11, 2013, 08:29 AM   #9
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jehu, what's the difference between FMJ bullets and PMJ bullets? Both have jackets the rifling engraves. I don't know of any barrels' rifling that's smart enough to tell the difference. And some of the finest, most accurate match bullets ever made were all FMJ ones from Lapua and Norma. In fact, all match bullets were FMJ's until the 1950's.

Sorry, PMJ bullets are partial metal jacketed ones. Hollow and soft point ones, for example.
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Old March 11, 2013, 04:21 PM   #10
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Yup.
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Old March 12, 2013, 05:33 AM   #11
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Quote:
Quote:
Quote:
Usually they are interchangeable: some related links.
http://answers.yahoo.com/question/in...5154413AAqrYDu
http://www.303british.com/id36.html
http://www.ar15.com/forums/t_6_2/377...62.html&page=2
http://how-i-did-it.org/762vs308/chamber.html
The very first link repeats the myth that 7.62x51 is 50,000PSI It's 50,000
CUP not PSI Quit mixing up units please. Tried of seeing that misinformation repeated over and over again..
Very true. Sadly if the wrong info is posted in a thread it stays there for ever and ever.

The difference between 7.62 and .308 is a slight difference in max headspace and the 7.62 brass is thicker and has less volume. It's insignificant.
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Old March 12, 2013, 06:10 AM   #12
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lol One is seven point six two millimeters and the other is three hundred and eight thousandths of an inch.
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Old March 12, 2013, 06:51 AM   #13
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Bart, I'm sure you are rite but when I think of FMJ I think of all the different countries that make it and are imported into the US and the possibilities of variations in production and specs. Some FMJ is or was laqure coated, Wolf was I think,and as a rule for me I'm not going to shoot it thru my fine bolt hunting gun. If you like it shoot it.
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Old March 12, 2013, 08:28 AM   #14
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I've never heard of any coatings on military bullets from any country. Some cases were coated but that proved to be a problem. Wolf no longer manufactures ammunition with a lacquer coating on the cartridge case due to issues concerning lacquer-coated steel cartridges becoming stuck in the chamber of a firearm after firing, with difficulty in ejecting the spent cartridge afterwards.
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Old March 12, 2013, 11:24 AM   #15
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OK, you may be rite but the jackets on FMJ are harder than copper jackets on premium hunting ammo which common sense tells me would wear more on my barrel and rifling but that being said why would anyone site in their fine bolt action hunting rifle with FMJ when in most states it's illegal to hunt with and unethical to shoot game with. Now yes it's their rifle and they can do what they want with it but to me it does'nt make any sense and I would recomend not doing it. Also your first two sentences in your above post are conflicting but lets say no country does coatings anymore but bubba from down the street has some old Wolf coated with lacquer and sells it to the original poster and he gums up his fine bolt action hunting rifle, I was just trying to give the best advise as I see it.

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Old March 12, 2013, 12:32 PM   #16
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jehu, I don't think my first two sentences in my post are conflicting. The first one's about bullets; the second about cases. The third sentence covers bubba's old Wolf cases coated with lacquer sold to the original poster and he gums up his fine bolt action hunting rifle. Wolf only coated cases, not bullets.

Less than 2% of barrel wear is caused by bullet jackets; they're much softer than barrel steel. The other 98%'s caused by hot buring gasses at high pressure and improper cleaning; virtualy all in the first inch or two of the rifling. If that weren't true, then bore and groove diameters starting a few inches down the bore would not remain virtually the same for thousands of rounds. Some folks have set back .308 Win. barrels 2" twice from starting out at 28 inches long and no accuracy degradation's been observed after 5000 to 7000 rounds per length..
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Old March 12, 2013, 12:47 PM   #17
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Thankyou for the information Bart. Is Military 7.62x51 FMJ loaded to higher pressure than civilian 308 hunting rds as I've heard 5.56 is compared to 223rem?
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Old March 12, 2013, 02:16 PM   #18
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MIL SPEC 7.62 NATO ammo for USA manufacture is 50,000 CUP (60,200 PSI) max average peak pressure.

SAAMI specs for commercial USA .308 Win. ammo is 52,000 CUP (62,000 PSI) max average peak pressure.
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Old March 13, 2013, 07:32 AM   #19
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Quote:
Is Military 7.62x51 FMJ loaded to higher pressure than civilian 308 hunting rds as I've heard 5.56 is compared to 223rem.
A insignificant difference.

in·sig·nif·i·cant

: not significant: as
a : lacking meaning or import
b : not worth considering : unimportant
c : lacking weight, position, or influence : contemptible
d : small in size, quantity, or number


Quote:
I've heard 5.56 is compared to 223rem
Again, insignificant. There is a difference in leade, but it's...insignificant.
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Old March 13, 2013, 01:20 PM   #20
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308 and 7.62X51

Sir;
The loading manuals make no distinction between the two, but the nato round pressure is supposed to be 50,000 C.U.P. and the 308 is around 52,000 C.U.P. and, furthermore the headspacu guage for the nato is slightly more allowable than the 308.
Great deals have been made about this but there is no difference for all intents and purposes.
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Old March 13, 2013, 02:24 PM   #21
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Quote:

The very first link repeats the myth that 7.62x51 is 50,000PSI It's 50,000 CUP not PSI Quit mixing up units please. Tried of seeing that misinformation repeated over and over again..
Average operation pressure of 7.62 NATO M80 Ball is 48,000 CUP or 50,000 PSI EPVAT ( the international standard).
The operating pressure of M118 Special Ball and M118 LR are 52,000 CUP, no EPVAT equivalent given.
HPT (military Proof loads) are 64,000 CUP.

Theres no direct correlation between CUP and PSI readings and the difference varies from one cartridge type to another because of differing case capacities and configurations. A few cartridges such as the .30 carbine have CUP and PSI figures that are identical.

PS
Most Milspec propellents contain flash suppressant and coolant additives , usually Calcium based, that add an abrasive element to fouling and increase bore wear.
As for laquer sealents at the case mouth and asphaltum sealants inside the case neck, I've cleaned enough military rifles to know that these do leave deposits in a bore.
Laquer coated steel cases are a problem on their own, and the waxy protective coating found on some older brass MG cartridges may have a deletrious effect when used in a rifle. Only heard of wax coating used on some South African .303 MG ammo placed in long term storage.

Last edited by Rainbow Demon; March 13, 2013 at 02:33 PM.
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Old March 13, 2013, 04:12 PM   #22
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R. Demon, your comments on the asphaltum sealant in military ammo case necks and additives in powders used in them don't reflect what I've experienced. They've have had no impact on accuracy and barrel life in both myself as well as many others wearing out match grade barrels. We've got the same accuracy fall off with 7.62 military sealed ammo with additives in powder and commercial .308 unsealed ammo with no additives in powder for the life of the barrels. It is the same rouind count as one of the USA's best match bullet makers got with their match grade barrels testing 30 caliber match bullets for accuracy. Typically 3000 rounds before accuracy degraded by 30 to 40 percent. The same number test barrels used at the arsenal got testing 7.62 match and service grade ammo; all with asphaltum and powder additives you mention as told to my by one of their ballistic engineers. Therefore I can only conclude that all those addititives and sealants have no effect on neither barrel life nor accuracy.

I've not noticed any significant difference in how dirty barrels were whether or not additives or sealant was in the ammo or not. And I've worn out more than a few barrels with both ammo types.
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Old March 13, 2013, 08:45 PM   #23
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Just like .223/5.56 and .308/7.62 if there was such a big danger that some keyboard commandos make it out to be manufacturers would have come up with one standard many many years ago. Could you just imagine all the lawsuits for blown up guns. Trial lawyers would have have a field day. Fact is its a non issue.
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Old March 13, 2013, 09:20 PM   #24
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I'm sure matchgrade barrels get far better and more frequent cleanings than the milsurp rifle barrels I've cleaned up over the years.
I've cleaned up bores with grooves packed solid with fouling hardened by decades of storage without ever having been properly cleaned. When finally broken loose it comes out in palm fulls.

Any grit introduced into propelents can be a factor in wear.
The older ground glass added to sensitise primers for example, before barium salts were substituted.


Some milsurp ammo I've broken down for components had globs of sealant that intruded into the powder space, properly assembled ammo should have no more than a smidgeon near the case mouth.

I've made scrapers from brass tubing to clear out fouling from the chamber neck that was thick enough to cause excessive pressures when a cartridge was fired.
The hardened fouling looked like scrappings from an old phonograph record, coming out in thin coils. A dry crusty deposit under that looked more like graphite and came out in dusty granules.
Never saw anything like it on any commercial firearms no matter how abused.

With an SKS I cleaned up a couple of years back the fouling dissolved in the solvent into a laquerlike mess that took forever to get out.
The bore looked like a patch soaked in stock finish had been run through it till it was all gone. That had to have come from the asphaltum sealant and laquer case coating of Soviet ammo.

If every type of milspec ammo was as well put together as US government ammo there'd be little to worry about on these scores.
Some NATO interchangeable ball is atrocious.
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Old March 14, 2013, 06:42 AM   #25
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Lots of good info from knowledgeable and experenced guys.My conclusion for myself and advise to others would still be, as a general rule, not to run anybodys FMJ in your fine bolt action hunting rifle. Stick to premium hunting ammo.
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