.308 vs. 7.62x51

[FrostyLeaves2]

Soo... I shoot .308 and that's what I will use when hunting... But I'm going to walk into the woods later today and just do some "plinking" with my uncle.. And I was wondering if there really is a difference a major difference that I shouldn't use any of the 7.62x51 in my .308 rifle just to do some target shooting... So let's see what people have to say

[88GW]

No big deal.  I have a .308 chambered rifle and handgun and shoot 7.62x51 out of both of them with no problem.  Ballistics are slightly different than my hunting loads but still good for plinking.

[Hock3y24]

Bolt action? I do it all the time in mine with no issues.

[Mr VJP]

Everything you could ever want on the subject is here.

 

https://www.google.com/search?q=.308+vs.+7.62x51&espv=2&biw=1366&bih=667&tbm=isch&imgil=KsjmOv6doa6SwM%253A%253BlzQ-g9ArTec1eM%253Bhttp%25253A%25252F%25252Fwww.303british.com%25252Fid36.html&source=iu&pf=m&fir=KsjmOv6doa6SwM%253A%252ClzQ-g9ArTec1eM%252C_&usg=__Gx-ggKhDDuDoUpsMb8trykEIQTA%3D&ved=0CDEQyjc&ei=y1xGVKGcBMvlsASixoCYBA#facrc=_&imgdii=_&imgrc=thr1C2P2QF1huM%253A%3BVuIqtmDJs-iudM%3Bhttp%253A%252F%252Fi203.photobucket.com%252Falbums%252Faa98%252Flittletoyzero%252Fhk20case20separations_zps424c86bd.jpg%3Bhttps%253A%252F%252Fwww.ar15.com%252Farchive%252Ftopic.html%253Fb%253D6%2526f%253D49%2526t%253D417914%3B640%3B509

[FrostyLeaves2]

Thanks all of you, I'll have to take a look at that link and yes bolt action..

[wildcat junkie]

7.62 X 51 = .308 Win  just like 5.56 X 45 =.223 Rem.

 

One is the metric miltary terminology, the other is civilian commecial terminology.

 

No difference as far as the caliber or case dimensions. Military is FMJ, civilian is expanding bullet.

Edited December 7, 2014 by wildcat junkie

[irish_redneck]

Wrong about .223 at least. I know for certain that .223 can be shot from a 5.56 , but not other way round. Head spacing makes for unsafe pressure with a rifle stamped as .223 rem

Edited December 7, 2014 by irish_redneck

[wildcat junkie]

Wrong about .223 at least. I know for certain that .223 can be shot from a 5.56 , but not other way round. Head spacing makes for unsafe pressure with a rifle stamped as .223 rem

Interesting that the .223 round will properly headspace in a 5.56X45 chamber while the 5.56X45 will not properly headspace in a 223 chamber. Would you please post the dimensional case data that would cause this.

 

There is a difference in pressure that has nothing to do with the cartridge dimensions that would effect headspace.

[Setters4life]

Good read on headspace, brass, dimensions, etc. describing the subtle differences. It's something you should be aware of particularly when dabbling with mil-spec semi-auto rifles.

 

http://www.fulton-armory.com/%5Cfaqs%5CM14-FAQs%5C308.htm

 

[irish_redneck]

Sorry headspace was wrong term. Leade and throat is what's different. (I don't reload, but do have a .223 stamped firearm)

[irish_redneck]

http://blog.cheaperthandirt.com/223-rem-5-56-exhaustive-review/

[Mr VJP]

The above link is a good read on the .223 vs 5.56 and sums up the issue very well.  A "TRUE" 5.56 round fired in a rifle with a "REAL" .223 chamber can give you dangerously high pressure levels.  The details are many and are all covered in that article.

 

The problem with .308 vs 7.62x51 is more of a rifle issue than a cartridge issue.  The cartridges are basically the same, but the military case is thicker, having less capacity, and if reloaded as a "max" load listed for thinner commercial brass, can give unsafe higher pressures when fired.  

 

A rifle, most often of the military type, may have a chamber that will cause commercial .308 Win brass to stretch, because it is thinner than military brass and the military chamber is slightly longer.  That can cause case separation issues.

 

If you really want to know what is safe to fire in YOUR rifle, you can only tell by finding out what your chamber specs are.  That means throat and leade as well.  That's the only way to truly tell what your rifle is really capable of safely firing.

[wildcat junkie]

Sorry headspace was wrong term. Leade and throat is what's different. (I don't reload, but do have a .223 stamped firearm)

That makes sense.

[Setters4life]

When I took ownership of a match M1A many years ago, it was shipped with a card that noted the headspace measurement of the rifle. At the time, I thought that was neat but "why would I need it?"

 

Over the years, I would learn a few things, and this article explains some.

http://www.zediker.com/downloads/14_loading.pdf