Can I use 308 for 7.62X51 ?


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CARSON
January 8, 2004, 08:50 PM
I am thinking of buying a Norinco in 7.62X51, but I can find no load data, dies, or brass for it. I know it is almost identical to the 308, but is it close enough to use the above components to load for it accuratley and reliably? If not, can you please tell me where I can find what I am looking for.

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Art Eatman
January 8, 2004, 11:29 PM
They're the same animal. Caveat: Check the comparative case capacity between military cases and commercial cases. Some (All? Dunno.) military brass has thicker case walls, and using a max load for commercial brass can result in pressures which are too high.

Many people recommend small-base dies when loading for use in a semi-auto. Makes extraction more reliaible.

Art

stans
January 9, 2004, 07:34 AM
Not really the same animal, but close enough that no one can tell the difference. There are very slight differences in cartridge dimensions, primarily in the extractor groove and case head, but functionally they are interchangeable. Military brass tends to be thicker, so if you reload mil-spec brass, reduce your powder charge. Also, commercial brass is sometimes softer, Remington brass seems to have the most comments in this regard, than military brass, so torn rims can occur during case extraction.

FireInTheHole
January 9, 2004, 10:38 AM
Comparison:

42gr of WCC846 under a 147gr FMJ in a cavim '84 case yields me ~ 2650fps from my 18" FAL

whereas 45gr of the same powder in a winchester .308 case gives me ~ 2700fps.

I dont play with [costly] commercial powders, but I feel the numbers are significant.

Sunray
January 9, 2004, 12:38 PM
Yes, just use the same data. The .308 and 7.62 Nato are the same thing. The only time I've ever seen any debate about this in 30 plus years was when I first started reading these forums. We sold all kinds of Portugese 7.62 to guys with Model 70a Police rifles, FN's, M1A's and never once had a problem.
Military cases are a tic thicker though so back off 10% and work up.

Dave R
January 9, 2004, 01:17 PM
FYI Speer #13 reloading manual give their .308 Win data using mil-spec brass, so no adjustment is needed from the Speer loads. Which also confims it is OK to reload that military brass. Just be sure to remove the military primer crimp as needed.

Publicola
January 11, 2004, 04:24 PM
It's not the same.

The cartridge headspace for 7.62x51mm & .308 Winchester are close enough to be interchangable. However the chamber headspace is not. The 7.62x51mm chamber will have excessive headspace when using a .308 Winchester cartridge. It gets away with this in 7.62x51mm cartridges because the brass is thicker & only fired once.

http://www3.sympatico.ca/shooters/7_62vs308.htm

http://www.fulton-armory.com/308.htm

http://www.armalite.com/library/techNotes/word97_docs/tnote11.doc

http://www.thegunzone.com/30cal.html

http://outdoorsbest.zeroforum.com/zerothread?id=87590

http://users.adelphia.net/~22x9/gaarchive/arc1-001.html

The last one is a post using info based on Jerry Kuhnhausen's book The U.S. .30 Caliber Gas Operated Service Rifles , A Shop Manual , Volumes I & II.

A lot of people will contend there is no difference & they'll shoot .308 Winchester in 7.62x51mm rifles without incident. But I prefer to play it safe & i recommend not confusing the two chamberings.

So my advice is either plan on using surplus ammo only in a 7.62x51mm rifle, or have a 'smith throw on a new barrel that conforms with .308 Winchester headspace specs.

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