7.62 NATO question

[SkyDaver]

Someone I know made the statement that .308 Winchester and 7.62 NATO are different.

He said that .308 Winchester is 7.62mmx51mm, and 7.62 NATO is 7.62x54mm. (and .30-06 is 7.62mmx63mm)

over an IM channel (and this guy is terse and cryptic when he types) he then wrote "ALL THREE ARE DIFFERENT but headspaces are similar (within tolerances) between 308 and NATO. you can get away with it, but high pressures are the result"

From www.reloadbench.com, I get the impression that 7.62NATO was renamed .308 Winchester by Winchester, and is exactly the same.

Is either of these correct, or is the correct answer somewhere in the middle?

Thanks,

 

[R.H. Lee]

7.62 NATO is 7.62 x 51. There is a slight difference between .308 and 7.62 x 51 in the shoulder angle IIRC.

 

[rritter]

They're very close, but not identical. Here's a link that gives a good explanation. I believe it's safer to use .308 in a 7.62 NATO chamber than the other way around, but as the linked article points out you're still taking a chance.

Both .308 Winchester and 7.62 NATO can be described as 7.62x51mm. The only 7.62x54mm I know of is the old rimmed Russian rifle round, generally called 7.62x54R, that was used from about 1891 on.

Roger

 

[MrMurphy]

7.62X39mm: What the AK uses.

7.62X51mm: Nato round, slightly different from the .308 but they fire in the same guns.

7.62X54 R: The Russian service rifle round from 1891-1947, still used in the PKM machine guns and the Dragunov sniper rifle. Longest-serving centerfire rifle round in existence.

7.62X63mm: The .30 M1, U.S Government Model of 1906 (.30-06).

 

[kaferhaus]

308 Win and 7.62x51 NATO case dimensions are identical, don't let anyone tell you different.

Military barrels chambered for the NATO round generally have slightly longer throats.

Commercial 308 win ammunition is generaly loaded to higher pressures than the NATO ammo.

 

[SkyDaver]

Thanks to all

 

[Dave R]

Just a confirming note from the world of Reloading...

Speer No. 13 strongly implies (but does not state outright) that you can use the two interchangeably in a .308 rifle. Its notes only that NATO brass is thicker. That could cause higher pressures at max loads. When using older load data, it says you should drop a grain from max loads. Then it goes on to say that the loads in Speer No. 13 were developed using NATO-spec brass and do not require a reduction in max loads. USUAL DISCLAIMERS APPLY. START AT MIN AND WORK UP, WATCHING FOR PRESSURE SIGNS IN YOUR RIFLE. It also notes loads that are recommended for gas-operated semi-autos, such as M1A and FAL.

I shoot NATO surplus in my Rem700. No signs of ill effects so far. I DO NOT shoot commercial .308 in my CETME, since its vigorous extraction is reputed to rip commercial case heads off.

 

[kaferhaus]

Several years ago I performed the "water capacity test" on US manufactured NATO spec brass and 308 commercial brass.

The difference averaged about half a grain!! nearly nothing in other words (all brass was full length resized and trimmed to the same length).

HOWEVER, the israeli, south african and portugese brass held on average a full 2 grains less.

So the manuals are correct (as they usually are) on exercising care when using reclaimed military brass.

 

[SMLE]

Click this link for a very good essay on this subject.

http://www.smellysmleshooters.net/ammopressure.htm

 

[jacketch]

Good comparison of 7.62x51 and .308 at FalFiles