7.62mm .308 differences???

Re: 7.62mm .308 differences???

Opinion? its a fact, commercial .308 is hotter than Nato 7.62 The end!

Do not shoot .308 in a rile marked 7.62, its ok to shoot 7.62 out of a rifle marked .308 but I dont know why you would want to.
 
Re: 7.62mm .308 differences???

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tucsondave</div><div class="ubbcode-body">OK,so what is the general consensus regarding the 7.62mm vs. the .308? Are they the same? Can you shoot the 7.62 from a .308 or vice aversa? Should the two never mix? Just trying to get the "facts"and do the right thing. Thanks </div></div>

The difference is in the chambers, not the outside dimensions of the two cartridge cases. The difference pressure-wise is negligible. The biggest concern relates to port pressure restrictions of the M1/M14 platform, for which the slow burn rate powders used in most commercial .308 loads is not suitable.

Don
 
Re: 7.62mm .308 differences???

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tucsondave</div><div class="ubbcode-body">Thanks for your opinion. My HK 91 is marked 7.62/.308 </div></div>

As long as it says .308, its a .308. Any military rifle marked 7.62 is 7.62 and most would agree that it would be unsafe to shoot .308 ammo out of.

.308 mag pressure is 62,000 psi

7.62 max pressure is 60,200 psi

This subject has been beaten to death a billion times, a quick search would yield a lot of results.
 
Re: 7.62mm .308 differences???

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: USSR</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tucsondave</div><div class="ubbcode-body">OK,so what is the general consensus regarding the 7.62mm vs. the .308? Are they the same? Can you shoot the 7.62 from a .308 or vice aversa? Should the two never mix? Just trying to get the "facts"and do the right thing. Thanks </div></div>

The difference is in the chambers, not the outside dimensions of the two cartridge cases. The difference pressure-wise is negligible. The biggest concern relates to port pressure restrictions of the M1/M14 platform, for which the slow burn rate powders used in most commercial .308 loads is not suitable.

Don </div></div>
This is correct. The chamber of a 7.62 Nato is about .0025 larger in the base diameter and .001 larger at the shoulder diameter some would even be bigger. This would infact reduce the chamber pressure if using commercial 308 Winchester ammunition in a 7.62 Nato chamber . So the Nato ammo could produce a bit higher pressure in a standard 308 Winchester chamber .
In reality the difference is negliable in a bolt action IMHO.
 
Re: 7.62mm .308 differences???

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tucsondave</div><div class="ubbcode-body">OK,so what is the general consensus regarding the 7.62mm vs. the .308? Are they the same? Can you shoot the 7.62 from a .308 or vice aversa? Should the two never mix? Just trying to get the "facts"and do the right thing. Thanks </div></div>

http://www.6mmbr.com/308Win.html

http://www.303british.com/id36.html

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

http://www.cruffler.com/trivia-June01.html


Chris


































 
Re: 7.62mm .308 differences???

Well, ALL my FGMM ammo is marked .308 and I shoot it out of semi-autos ALL the time(M1A, SR-25, HK91).........
OH-I also shoot 7.62X51mm out of my .308s too(BLR, Remmy bolt and auto)........
NEVER had an issue in my 50 yrs. of shooting.
The PSI #'s listed above are MAX as in "proof testing". NOT every day loads.......
Respectfully,
LG
 
Re: 7.62mm .308 differences???

"Military ammunition is loaded to maximum average pressure 50,000 PSI using the modern piezo transducer method of measurement. This standard is used to ensure better consistency round to round. It is proofed at 67,000PSI. The ammunition can then be used in a wide variety of firearms with no ill effects."

"Commercial ammunition has a SAAMI/ANSI maximum pressure of 62,000PSI. While not every manufacturer may load it to this level, this is the industry established maximum. This is also measured using the piezo transducer method. The proof cartridge pressure is 83,000 to 89,000 PSI. Note the differences between the military test and operational standard vs the commercial one."


From the second link I posted above.

Proof presures are pretty much insane.

Chris
 
Re: 7.62mm .308 differences???

You can use a .380 semi auto in a 9MM luger, but not a 9mm in a .380... Difference in neck size of case is very small. I have used them myself... Not good to do but I have done it..
 
Re: 7.62mm .308 differences???

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: eddieo</div><div class="ubbcode-body">You can use a .380 semi auto in a 9MM luger, but not a 9mm in a .380... Difference in neck size of case is very small. I have used them myself... Not good to do but I have done it.. </div></div>

They headspace off the case mouth, how do you get the primer to hit the .380?
 
Re: 7.62mm .308 differences???

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bigwheeler</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: eddieo</div><div class="ubbcode-body">You can use a .380 semi auto in a 9MM luger, but not a 9mm in a .380... Difference in neck size of case is very small. I have used them myself... Not good to do but I have done it.. </div></div>

They headspace off the case mouth, how do you get the primer to hit the .380? </div></div>

They hang off the extractor and just end up short.

Edit:

Still dangerous and I'd never do it on purpose....thus why I check my 9mm ammo, because I've had a few .380 cases sneak their way in before.
 
Re: 7.62mm .308 differences???

Chris, that info is incorrect...

check the current pressure standards for 7.62x51 NATO, almost the same as 308 Win (only meaningful diference is measured in a 7.62 instead of a commercial 308 chamber), it uses the same transducer location as CIP standards:

http://en.wikipedia.org/wiki/NATO_EPVAT_testing

The SAAMI does not list the 308 Win and 7.62x51 NATO in their famous list of "unsafe combinations" (but does list the 5.56 vs the 223 because they do have a different pressure).
http://www.saami.org/Unsafe_Combinations.cfm

As Don said:

"The difference is in the chambers, not the outside dimensions of the two cartridge cases. The difference pressure-wise is negligible. The biggest concern relates to port pressure restrictions of the M1/M14 platform, for which the slow burn rate powders used in most commercial .308 loads is not suitable."
 
Re: 7.62mm .308 differences???

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TiroFijo</div><div class="ubbcode-body">Chris, that info is incorrect...

check the current pressure standards for 7.62x51 NATO, almost the same as 308 Win (only meaningful diference is measured in a 7.62 instead of a commercial 308 chamber), it uses the same transducer location as CIP standards:

http://en.wikipedia.org/wiki/NATO_EPVAT_testing

The SAAMI does not list the 308 Win and 7.62x51 NATO in their famous list of "unsafe combinations" (but does list the 5.56 vs the 223 because they do have a different pressure).
http://www.saami.org/Unsafe_Combinations.cfm

As Don said:

"The difference is in the chambers, not the outside dimensions of the two cartridge cases. The difference pressure-wise is negligible. The biggest concern relates to port pressure restrictions of the M1/M14 platform, for which the slow burn rate powders used in most commercial .308 loads is not suitable."
</div></div>

Well, it just looks like they bumped the std. Mil pressure up 10k psi to 60k and the proof pressure up 8k psi to 75k. Maybe better testing protocols and/or stronger brass?

Here are the sources for the info you stated was incorrect:

"Sources: .308 Winchester data from ANSI/SAAMI document Z299.4-1992, Pressure and Velocity, Centerfire Rifle Sporting Ammunition

7.62 x 51mm NATO headspace data from Jerry Kuhnhausen's M1/M1A shop manual.

Pressure data from TM 43-001-27: Army Ammunition Data Sheets Small Caliber Ammunition"

Obviously, there are lots of people shooting NATO 556 in commercial bolt guns without incident. Still, I'd feel safer shooting commercial 308 out of my HK91/FN-FAL than I would +556 in a bolt gun, but it's no bother for me.

Take care, Chris
 
Re: 7.62mm .308 differences???

Chris, I know these sources
smile.gif


The 7.62x51 NATO pressure has not changed really, only the testing protocols have... it goes to show how tricky these pesky testing standards are. The US military had (...probably still has) one, SAAMI another, and CIP yet another.

If there were anything true in the "62.000 vs 50.000 PSI" you can be sure it would be in the SAAMI "unsafe combinations" list. After all the 5.56x45 (62.350 PSI) vs 223 Rem (55.000 PSI) is there.