I just bought a Ishapore Lee-Enfield 2A1 chambered in a 7.62x51 nato, Can i shoot 308 win though it safty i been trying to research it on my own but some web sites say you can and some say you cant.
7.62 nato vs 308 win
- Thread starter experthunter017
- Start date
Re: 7.62 nato vs 308 win
I have really hit the books on this very subject. I am still unclear as to all of the specifics, but I feel confident in my knowledge of a few points. I really got curious when I bought two offerings from Federal. Both were Federal Gold Medal Match (FGMM). Both used the 175gr Sierra Match King. But one was marked as .308 and the other was marked 7.62x51. The boxes showed different ballistics, but on federal's sight, they were listed as one round, completely interchangeable. That didn't make sense for a few reasons. 1) the boxes listed differences. 2) Know the .308 has different dimensions and usually different chamber pressure. So I contacted Federal and they saii that the website was wrong and that they load them differently to achieve the same ballistics. The FGMM 7.62 has a duller case than the polished brass on the .308. Also the FGMM has a crimped primer. I would guess for more stability, maybe for machine guns. So that particular question about the FGMM 175 gr. has not been answered. But in general, 7.62 NATO/military ammo has thicker casing walls to be able to stand up to full auto fire (M60, etc). That would seem to reduce the powder capacity, maybe thus reducing the pressure? In short, I would not fire .308 in your gun. If it's loaded like most .308 rounds (higher pressure), you could damage your firearm or worse, yourself.
I have really hit the books on this very subject. I am still unclear as to all of the specifics, but I feel confident in my knowledge of a few points. I really got curious when I bought two offerings from Federal. Both were Federal Gold Medal Match (FGMM). Both used the 175gr Sierra Match King. But one was marked as .308 and the other was marked 7.62x51. The boxes showed different ballistics, but on federal's sight, they were listed as one round, completely interchangeable. That didn't make sense for a few reasons. 1) the boxes listed differences. 2) Know the .308 has different dimensions and usually different chamber pressure. So I contacted Federal and they saii that the website was wrong and that they load them differently to achieve the same ballistics. The FGMM 7.62 has a duller case than the polished brass on the .308. Also the FGMM has a crimped primer. I would guess for more stability, maybe for machine guns. So that particular question about the FGMM 175 gr. has not been answered. But in general, 7.62 NATO/military ammo has thicker casing walls to be able to stand up to full auto fire (M60, etc). That would seem to reduce the powder capacity, maybe thus reducing the pressure? In short, I would not fire .308 in your gun. If it's loaded like most .308 rounds (higher pressure), you could damage your firearm or worse, yourself.
Re: 7.62 nato vs 308 win
A couple key differences:
7.62 has a max. pressure of 50k psi, while .308 is 62k psi.
Headspace is longer on a 7.62, but the acceptable range overlaps.
Case capacity of 7.62 is often a grain or more less than .308.
It's therefore usually safe to shoot 7.62 ammo in a .308, but not necessarily the other way around.
John
A couple key differences:
7.62 has a max. pressure of 50k psi, while .308 is 62k psi.
Headspace is longer on a 7.62, but the acceptable range overlaps.
Case capacity of 7.62 is often a grain or more less than .308.
It's therefore usually safe to shoot 7.62 ammo in a .308, but not necessarily the other way around.
John
Re: 7.62 nato vs 308 win
Thanks guys for clearing this up. After reading all the infromation you provided i went out and bought 250 7.62x51 NATO rounds. so that should hold me over for alittle while.
Thanks guys for clearing this up. After reading all the infromation you provided i went out and bought 250 7.62x51 NATO rounds. so that should hold me over for alittle while.
G
Guest
Guest
Re: 7.62 nato vs 308 win
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jhnmdahl</div><div class="ubbcode-body">A couple key differences:
7.62 has a max. pressure of 50k psi, while .308 is 62k psi.
Headspace is longer on a 7.62, but the acceptable range overlaps.
Case capacity of 7.62 is often a grain or more less than .308.
It's therefore usually safe to shoot 7.62 ammo in a .308, but not necessarily the other way around.
John </div></div>
7.62 max pressure is 50,000 CUP, not PSI.There is no way to convert one to another, and most GI ammo is loaded to near 62,000 psi when measured with that method.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jhnmdahl</div><div class="ubbcode-body">A couple key differences:
7.62 has a max. pressure of 50k psi, while .308 is 62k psi.
Headspace is longer on a 7.62, but the acceptable range overlaps.
Case capacity of 7.62 is often a grain or more less than .308.
It's therefore usually safe to shoot 7.62 ammo in a .308, but not necessarily the other way around.
John </div></div>
7.62 max pressure is 50,000 CUP, not PSI.There is no way to convert one to another, and most GI ammo is loaded to near 62,000 psi when measured with that method.
Re: 7.62 nato vs 308 win
SW, true enough - my mistake (or at least my repetition of another's mistake).
SW, true enough - my mistake (or at least my repetition of another's mistake).
L
longguntoter
Guest
Re: 7.62 nato vs 308 win
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jhnmdahl</div><div class="ubbcode-body">A couple key differences:
7.62 has a max. pressure of 50k psi, while .308 is 62k psi.
Headspace is longer on a 7.62, but the acceptable range overlaps.
Case capacity of 7.62 is often a grain or more less than .308.
It's therefore usually safe to shoot 7.62 ammo in a .308, but not necessarily the other way around.
John </div></div>Thanks, that's good to know! Seems just the opposite with the 5.56mm vs. the .223 Remington. 5.56mm chambers easily handle the .223, but not the other way around.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jhnmdahl</div><div class="ubbcode-body">A couple key differences:
7.62 has a max. pressure of 50k psi, while .308 is 62k psi.
Headspace is longer on a 7.62, but the acceptable range overlaps.
Case capacity of 7.62 is often a grain or more less than .308.
It's therefore usually safe to shoot 7.62 ammo in a .308, but not necessarily the other way around.
John </div></div>Thanks, that's good to know! Seems just the opposite with the 5.56mm vs. the .223 Remington. 5.56mm chambers easily handle the .223, but not the other way around.
Re: 7.62 nato vs 308 win
Well, as an owner of an ass load of Issy 2A and 2A1's I have to say this,
CAST YOUR CAMBER! As for shooting cheap 147 gr .308 in an Issy 2A1, if everything else checks out you'll be fine.
The Rifle, 7.62mm, 2A and 2A1 was the stopgap because the Indian gov had adopted the Rifle 1A (SLR for the UK(FAL for the rest)). Also should say India had its ass kicked in the 1962 China war. Rifle was made 1963-1973, rare dates are 70-73.
Now, after you cast the camber and see the long throat. Check the barrel for cord wear. Get some USGI 7.62 brass, pull down or Varget and 160gr .310 lead pills. You'll be driven tacs
Good luck!
Well, as an owner of an ass load of Issy 2A and 2A1's I have to say this,
CAST YOUR CAMBER! As for shooting cheap 147 gr .308 in an Issy 2A1, if everything else checks out you'll be fine.
The Rifle, 7.62mm, 2A and 2A1 was the stopgap because the Indian gov had adopted the Rifle 1A (SLR for the UK(FAL for the rest)). Also should say India had its ass kicked in the 1962 China war. Rifle was made 1963-1973, rare dates are 70-73.
Now, after you cast the camber and see the long throat. Check the barrel for cord wear. Get some USGI 7.62 brass, pull down or Varget and 160gr .310 lead pills. You'll be driven tacs
Good luck!
Re: 7.62 nato vs 308 win
Wow i will have t check this out more i was always under the impression that they were on in the same .. Good to know now i wont blow my self up ...
Wow i will have t check this out more i was always under the impression that they were on in the same .. Good to know now i wont blow my self up ...
Re: 7.62 nato vs 308 win
In case anyone is interested... CUP is what all ammunition is measured by. Stands for Copper Units of Pressure. There is no translation for PSI or KG/CM squared or similar...
Basically works when a copper disk is inserted in a pressure testing unit. When the round is fired, the copper disk is crushed by the pressure. This is translated into a number that is copper units of pressure.
When I was at Springfield Armory a few weeks ago, I saw testers. It might even have been invented at Springfield Armory. Next time I am down there, I will take some pictures.
Cheers,
Sirhr
In case anyone is interested... CUP is what all ammunition is measured by. Stands for Copper Units of Pressure. There is no translation for PSI or KG/CM squared or similar...
Basically works when a copper disk is inserted in a pressure testing unit. When the round is fired, the copper disk is crushed by the pressure. This is translated into a number that is copper units of pressure.
When I was at Springfield Armory a few weeks ago, I saw testers. It might even have been invented at Springfield Armory. Next time I am down there, I will take some pictures.
Cheers,
Sirhr
Re: 7.62 nato vs 308 win
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 3 Gun Runner</div><div class="ubbcode-body">Wow i will have t check this out more i was always under the impression that they were on in the same .. Good to know now i wont blow my self up ...
</div></div>
I was thinking the same
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 3 Gun Runner</div><div class="ubbcode-body">Wow i will have t check this out more i was always under the impression that they were on in the same .. Good to know now i wont blow my self up ...
</div></div>
I was thinking the same
Re: 7.62 nato vs 308 win
To add to and hopefully clarify this some what.
.308win. Saami has a 48,000 cup listing with a 52,000 cup working pressure.
7.62nato has a 60,000 listed pressure for what they are loading it to if this is as a CUP pressure measurement.
The military ammo is hotter. Period! I was told they are loading it to a higher pressure.
Now take a look at the chamber specs. The .308win. Saami chamber is a little tighter dimensionally than a 7.62nato. It's not necessarily the headspace you have to worry about. Lets assume the headspace on the 7.62nato gun you have measures the exact same length as your .308win. sammi gun does. If you look at the dimensions on the chamber drawings the 7.62nato chamber in some areas is bigger on the diameter of the chamber and if I remember correctly the throat of the chamber as well.
You take that 7.62nato ammo and run it in a .308win. Saami chamber and it will drive pressure up more.
You can take the .308win. Saami spec. ammo and run it in the looser (not headspace looser) nato chamber and pressure should drop a little. Not go up.
We make ammunition test barrels all the time and talk to the ammunition makers on a regular basis.
So I would be o.k. with shooting SAAMI ammo in a Nato chamber but not vice versa.
The 5.56mm nato ammo seems to be worse than .223Rem. in this regards of swapping etc...
Later, Frank
Bartlein Barrels
To add to and hopefully clarify this some what.
.308win. Saami has a 48,000 cup listing with a 52,000 cup working pressure.
7.62nato has a 60,000 listed pressure for what they are loading it to if this is as a CUP pressure measurement.
The military ammo is hotter. Period! I was told they are loading it to a higher pressure.
Now take a look at the chamber specs. The .308win. Saami chamber is a little tighter dimensionally than a 7.62nato. It's not necessarily the headspace you have to worry about. Lets assume the headspace on the 7.62nato gun you have measures the exact same length as your .308win. sammi gun does. If you look at the dimensions on the chamber drawings the 7.62nato chamber in some areas is bigger on the diameter of the chamber and if I remember correctly the throat of the chamber as well.
You take that 7.62nato ammo and run it in a .308win. Saami chamber and it will drive pressure up more.
You can take the .308win. Saami spec. ammo and run it in the looser (not headspace looser) nato chamber and pressure should drop a little. Not go up.
We make ammunition test barrels all the time and talk to the ammunition makers on a regular basis.
So I would be o.k. with shooting SAAMI ammo in a Nato chamber but not vice versa.
The 5.56mm nato ammo seems to be worse than .223Rem. in this regards of swapping etc...
Later, Frank
Bartlein Barrels
Re: 7.62 nato vs 308 win
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Frank Green</div><div class="ubbcode-body">
.308win. Saami has a 48,000 psi listing with a 52,000psi working pressure.
7.62nato has a 60,000 psi listed pressure. So either way you look at it the 7.62nato is around 10k more.
The military ammo is hotter. Period!</div></div>
Most sources say exactly the opposite, that .308 pressures are potentially higher than 7.62mm pressures. 7.62mm pressures I've found are also usually specified measured in CUP, which are typically somewhat lower than true PSI measured using modern strain gauge methods.
SWAmmo hit it on the head in his earlier post, indicating that military ammunition is loaded to 50,000 CUP max, which may or may not be around 58,000 true psi depending on who one asks, while commercial ammunition is loaded to 62,000 psi max. Proof pressures are similarly proportional, at 67,000 psi for 7.62mm military loads and 83,000-89,000 psi for .308 loads.
Here's a web page I found that summarizes the differences reasonably well:
http://www.303british.com/id36.html
and a few more for reference/confirmation:
http://www.6mmbr.com/308win.html
(scroll down to ".308 Win vs. 7.62x51--The Straight Scoop")
http://www.thegunzone.com/30cal.html
John
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Frank Green</div><div class="ubbcode-body">
.308win. Saami has a 48,000 psi listing with a 52,000psi working pressure.
7.62nato has a 60,000 psi listed pressure. So either way you look at it the 7.62nato is around 10k more.
The military ammo is hotter. Period!</div></div>
Most sources say exactly the opposite, that .308 pressures are potentially higher than 7.62mm pressures. 7.62mm pressures I've found are also usually specified measured in CUP, which are typically somewhat lower than true PSI measured using modern strain gauge methods.
SWAmmo hit it on the head in his earlier post, indicating that military ammunition is loaded to 50,000 CUP max, which may or may not be around 58,000 true psi depending on who one asks, while commercial ammunition is loaded to 62,000 psi max. Proof pressures are similarly proportional, at 67,000 psi for 7.62mm military loads and 83,000-89,000 psi for .308 loads.
Here's a web page I found that summarizes the differences reasonably well:
http://www.303british.com/id36.html
and a few more for reference/confirmation:
http://www.6mmbr.com/308win.html
(scroll down to ".308 Win vs. 7.62x51--The Straight Scoop")
http://www.thegunzone.com/30cal.html
John
Re: 7.62 nato vs 308 win
I won't disclose the ammunition manufacturer that is loading both SAAMI spec. .308win and they also load 7.62nato type ammo as well.
I looked it up in the SAAMI book. He told me pressure and I took it as PSI. The service maximum average pressure for the .308win. is 52,000 CUP.
Max service pressure using a transducer PSI method is 62,000psi. This again is according to SAAMI data for .308win.
Again if they are loading the NATO rounds to 60,000 psi. Keep in mind this reading is taken at the case mouth. Not on the case body like SAAMI does.
Sorry if I had the PSI and CUP mixed up. Didn't mean to confuse anyone.
Again this comes from guys I talk to that do the actual testing of the ammo.
Again they know for fact if you shoot a 7.62nato round in a Saami type chamber the pressure goes up.
Later, Frank
Bartlein Barrels Inc.
I won't disclose the ammunition manufacturer that is loading both SAAMI spec. .308win and they also load 7.62nato type ammo as well.
I looked it up in the SAAMI book. He told me pressure and I took it as PSI. The service maximum average pressure for the .308win. is 52,000 CUP.
Max service pressure using a transducer PSI method is 62,000psi. This again is according to SAAMI data for .308win.
Again if they are loading the NATO rounds to 60,000 psi. Keep in mind this reading is taken at the case mouth. Not on the case body like SAAMI does.
Sorry if I had the PSI and CUP mixed up. Didn't mean to confuse anyone.
Again this comes from guys I talk to that do the actual testing of the ammo.
Again they know for fact if you shoot a 7.62nato round in a Saami type chamber the pressure goes up.
Later, Frank
Bartlein Barrels Inc.
Re: 7.62 nato vs 308 win
You know,this never became a problem until we got the Internet came about.
We use to shoot both interchangeably. Since all my 308s are Pre Internet, I'll just keep on shooting.
Same with the 223 vs 5.56 arguments.
You know,this never became a problem until we got the Internet came about.
We use to shoot both interchangeably. Since all my 308s are Pre Internet, I'll just keep on shooting.
Same with the 223 vs 5.56 arguments.
Re: 7.62 nato vs 308 win
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kraigWY</div><div class="ubbcode-body">You know,this never became a problem until we got the Internet came about.
We use to shoot both interchangeably. <span style="color: #FF0000">Since all my 308s are Pre Internet, I'll just keep on shooting.</span>
Same with the 223 vs 5.56 arguments. </div></div>
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kraigWY</div><div class="ubbcode-body">You know,this never became a problem until we got the Internet came about.
We use to shoot both interchangeably. <span style="color: #FF0000">Since all my 308s are Pre Internet, I'll just keep on shooting.</span>
Same with the 223 vs 5.56 arguments. </div></div>
Re: 7.62 nato vs 308 win
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kraigWY</div><div class="ubbcode-body">You know,this never became a problem until we got the Internet came about.
We use to shoot both interchangeably. Since all my 308s are Pre Internet, I'll just keep on shooting.
Same with the 223 vs 5.56 arguments. </div></div>
That cracks me up! LOL! But it's the truth!
Later, Frank
Bartlein Barrels
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kraigWY</div><div class="ubbcode-body">You know,this never became a problem until we got the Internet came about.
We use to shoot both interchangeably. Since all my 308s are Pre Internet, I'll just keep on shooting.
Same with the 223 vs 5.56 arguments. </div></div>
That cracks me up! LOL! But it's the truth!
Later, Frank
Bartlein Barrels
G
Guest
Guest
Re: 7.62 nato vs 308 win
Simple civi test, add a Can to a 7.62X51 NATO chambered M1A. Turn off the gas spindle valve an fire a true Nato round first, then fire a .308win same bullet weight.
<span style="color: #FF0000">Not,... advising this at all,</span> but if you really want to know,...and are felling lucky,...go for it.
Please report back, on how long it took before you could cycle the bolt on the Nato vs the .308win. Don't cheat an shoot a Nato pressured .308win factory load and call it good.
46grs of BL-(C)2 in a mil case with a WLR primer pushing a crimped 147gr FMJBT will get you to Nato specs. That load tracks with std M14/M1A sights.
.308win vol's for that same rd is around 2900fps+ at true win pressure, Nato speed is approx 2750
Simple civi test, add a Can to a 7.62X51 NATO chambered M1A. Turn off the gas spindle valve an fire a true Nato round first, then fire a .308win same bullet weight.
<span style="color: #FF0000">Not,... advising this at all,</span> but if you really want to know,...and are felling lucky,...go for it.
Please report back, on how long it took before you could cycle the bolt on the Nato vs the .308win. Don't cheat an shoot a Nato pressured .308win factory load and call it good.
46grs of BL-(C)2 in a mil case with a WLR primer pushing a crimped 147gr FMJBT will get you to Nato specs. That load tracks with std M14/M1A sights.
.308win vol's for that same rd is around 2900fps+ at true win pressure, Nato speed is approx 2750
Re: 7.62 nato vs 308 win
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kraigWY</div><div class="ubbcode-body">You know,this never became a problem until we got the Internet came about.
We use to shoot both interchangeably. Since all my 308s are Pre Internet, I'll just keep on shooting.
Same with the 223 vs 5.56 arguments.</div></div>
Exactly! The only thing we ever watched out for was to lower the max loads 10% if reloading as the mil brass is thicker than civilian.
No trouble w/5.56/.223 either.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kraigWY</div><div class="ubbcode-body">You know,this never became a problem until we got the Internet came about.
We use to shoot both interchangeably. Since all my 308s are Pre Internet, I'll just keep on shooting.
Same with the 223 vs 5.56 arguments.</div></div>
Exactly! The only thing we ever watched out for was to lower the max loads 10% if reloading as the mil brass is thicker than civilian.
No trouble w/5.56/.223 either.
Re: 7.62 nato vs 308 win
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mike Hull</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kraigWY</div><div class="ubbcode-body">You know,this never became a problem until we got the Internet came about.
We use to shoot both interchangeably. Since all my 308s are Pre Internet, I'll just keep on shooting.
Same with the 223 vs 5.56 arguments.</div></div>
Exactly! The only thing we ever watched out for was to lower the max loads 10% if reloading as the mil brass is thicker than civilian.
No trouble w/5.56/.223 either.
</div></div>
Ah , but this new generation needs something to wring their hands about...as if they didn't have anything else to worry about! HA!
Heck , if I had the internet back in my day I would have died from all the 'dangerous' 'life threating' things that we used to do...and still do!
What we need is less hand wringing and more shooting!....but hen what would become of the internet? heh-heh
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mike Hull</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kraigWY</div><div class="ubbcode-body">You know,this never became a problem until we got the Internet came about.
We use to shoot both interchangeably. Since all my 308s are Pre Internet, I'll just keep on shooting.
Same with the 223 vs 5.56 arguments.</div></div>
Exactly! The only thing we ever watched out for was to lower the max loads 10% if reloading as the mil brass is thicker than civilian.
No trouble w/5.56/.223 either.
Ah , but this new generation needs something to wring their hands about...as if they didn't have anything else to worry about! HA!
Heck , if I had the internet back in my day I would have died from all the 'dangerous' 'life threating' things that we used to do...and still do!
What we need is less hand wringing and more shooting!....but hen what would become of the internet? heh-heh
Similar threads
