7.62x51mm vs. .308

[davemata]

Hey guys, been trying to figure this one out and I'm finding conflicting information. Can the 7.62x51mm be fired in a .308? I was looking at .308 prices, and was wondering if milsurp of the 7.62 would be cheaper, since I'm getting skunked on finding .308 milsurp.

I'm partial to my fingers and pretty face, so I figured it would be wise to ask.

 

[FPrice]

A couple of people (to include one self-proclaimed "expert") seem to think that the difference between 7.62x51 and .308 are not nearly as great as the 5.56 vs .223 differences. Since my rifles are 7,62x51 I've never had to concern myself with any difference. It will be interesting to see what some real experts think.

 

[davemata]

Most recent link I read implied that while a .308 round should never go into a 7.62 chambered rifle, it was ok to put the 7.62NATO into a .308 because the .308 was built to handle higher pressures.

It's all as clear as mud right now.

 

[NavelOfficer]

That's the way I understand it. I don't have the exact SAAMI pressures on the top-of-my-head, but the .308 Winchester does have the higher pressure rating. If you're shooting an FR-7 (any gun derived from the small-ring Mauser apparently), you'd be better to refrain from .308 Winchester (full-tilt loads), just to err on the safe side.
This is similar to the articles I've gleaned from:
http://www.303british.com/id36.html

 

[FPrice]

There is an M14/M1A forum, http://www.m14forum.com which could probably answer the question with much authority. I joined when I bought my M1A Scout Rifle and people there are pretty good about helping one another.

 

[r2nailer]

I have a DPMS/Panther Arms Heavy Barrel, (AR10)
and the website says do not use milsurp ammo

 

[davemata]

I'll check the M1 forum.

I recently picked up a Savage .308 (110 FP) from a member, and am just trying to learn as much as I can with it, so I know what I can and cannot do with it.

Since it's a .308 my assumption was that I could use 7.62 as cheap plinking stuff.

 

[FPrice]

I did a quick check and here is the thread:

http://m14forum.com/ammunition/100445-7-62-x-51-cartridge-vs-308-winchester-differences.html

Some good info there.

 

[davemata]

Read it, looks like 7.62 is cool in my .308, even if it runs hot.

Now, for double points, would love pm'ed suggestions of economical places to buy ammo in state. I *could* have stuff shipped to NH for me, but I'd rather buy from some local outfits provided it's not anything silly. Any places to get mil surplus?

DISCLAIMER - Not asking for mailorder outfits, I'm not going to violate that forum rule.

 

[BTSDOG]

The only difference between 7.62x51 and .308 are the inside dimensions of the case. Military brass (7.62x51) is usually thicker than commercial (308) brass. I have a springfield m1a supermatch and have shot both types of brass with no problems whatsoever. Hornady has a load book which shows loads for both types, and when loading in military brass always load .5 to 1 grain lighter than commercial brass. If your buying surplus 7.62 ammo, you should be careful that you are not buying delinked machinegun ammo, as this is usually loaded hotter than m118 or lc match ammo. If you start your loads at minimum, and work up, you should have no problems.................

 

[BearArms]

I have a DPMS/Panther Arms Heavy Barrel, (AR10)
and the website says do not use milsurp ammo

Had a DPMS LR. I've shot thousands of rounds milsurp through it without a problem.

 

[Len-2A Training]

I don't know anything about the ammo differences, but having recently obtained a couple of rifles (and found a stash of 7.62x51 that I bought years ago) where this info is applicable, I pulled together the following info that might be useful to others:

.308 v 7.62x51 specs (source: Cartridges of the World, 10[SUP]th[/SUP] Edition):

Case Type: C v. C (C=Rimless, Bottleneck)
Bullet Dia: .308 v. .308
Neck Dia: .344 v. .338
Shoulder Dia: .454 v. .447
Base Dia:.470 v. .466
Rim Dia: .470 v. .470
Rim Thickness: .049 v. (Did Not Find this info on 7.62x51 in this book)
Case Length: 2.01 (2.015) v. 2.01
Cartridge Length: 2.75 v. 2.75
Twist: 12 v. 12
Pressure: (Did Not Find this info on .308 in this book) v. 50,000 psi max avg

 

[AllaSnackbah]

i have always wondered about this with my M1A, i try to stick with 7.62x51 NATO as much as i can, from what ive read which is not much, nobody has any real definitive answer as to what you should or shouldnt do.

 

[CMEBoston]

My Springfield m1a is chambered for .308, the manual says to use 7.62 NATO. The NATO ammo does not run as high as the sammi spec .308. I have not had any issues with Winchester, Remington or PPU .308 in my M1A. When I handload i resize with an RCBS small base die marked .308...... I think, in the M1A's case it's a matter of pressure on the gas system rather than over pressuring the chamber. This is alleviated by using powders no slower than IMR4064 and bullets that weigh no more than 170 grains.


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[P. Lopes]

It's the same round, europeans use the metric system, they don't know what 308 means. Well, the brits do.

 

[bpm990d]

It was the U.S. that developed the.308 and the 7.62mm, not Europeans.

B

 

[P. Lopes]

i know, but it's still the same round. Nato countries use the metric system. 308 is 7x62mm.

 

[CMEBoston]

Don't confuse 7.62 NATO with .308 Winchester they are very different. This is because 7.62 NATO head spacing is much more generous than .308 Winchester due to the fact that military weapons must continue to operate when fouled or dirty due to use in battle.


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[50 BMG]

The pressure of a 308 Winchester round is higher as well. Go to http://207.36.233.89/index.asp search for the article explaining the difference between the rounds. its very informative. This is especially important for us Military surplus collectors when it comes to chamber pressures.

 

[improman]

very good decent ..thank you

 

[OfficerObie59]

I was always taught while the physical demesions of the casings were most of the time insignificant, it was the very reverse of the .223/5.56 issue when it came to pressure, with the .308's running hotter than the 7.62.

I have a DPMS/Panther Arms Heavy Barrel, (AR10)
and the website says do not use milsurp ammo

Any idea if that's because they don't want you shooting corrosive stuff in your gun, or because of size/pressue differnence?

 

[1903Collector]

i have always wondered about this with my M1A, i try to stick with 7.62x51 NATO as much as i can, from what ive read which is not much, nobody has any real definitive answer as to what you should or shouldnt do.

I read somwhere that SA sets headspace on the M1A in the middle-ish so you can safely fire commercial and military ammo. I forget what the actual numbers are, I've got em somwhere.

 

[KBCraig]

Milspec 7.62x51 ammo can safely be fired in chambers that are looser, or have longer headspace. Thin commercial brass might not be safe in the same chamber.

Milspec ammo will be safe in SAAMI commercial rifles.

From the people who literally wrote the book about M1 Garands and M14s:

http://www.fulton-armory.com/\faqs\M14-FAQs\308.htm

 

[NavelOfficer]

Since you're shooting a bolt gun, you should consider reloading. You're not limited to loads that must cycle your firearm, so you can economically produce reduced-load cast and jacketed rounds, if so desired.
Otherwise, just keep your eyes open for inexpensive surplus 7.62 NATO; it will work fine.
One caution ... "CBC 7.62 75"
See lower portion of the page... http://www.thegunzone.com/30cal.html

 

[FPrice]

One caution ... "CBC 7.62 75"
See lower portion of the page... http://www.thegunzone.com/30cal.html

Thanks for that warning AND the reference.

 

[CMEBoston]

I read somwhere that SA sets headspace on the M1A in the middle-ish so you can safely fire commercial and military ammo. I forget what the actual numbers are, I've got em somwhere.

FWIW My SAI Scout headspace is 1.631