.308 Win vs. 7.62 Nato?

[lgm270]

I'm kind of confused.  Considering a 7.62 Israeli Mauser and trying to figure out whether or not it can safely handle commercial .308 Win.   

Can we?   
 

[mannyrock]

  The 7.62 Nato and .308 Winchester are not the same round.  Although they are identical externally, the Nato round has thicker brass (for use in machine guns), which means that it holds less powder, and creates lower pressure.  The .308 Winchester is a hunting round, with thinner brass, more powder, and higher pressure.

   I think the Nato round has about 52,000 psi.  The .308 Winchester is much higher, with a sammi pressure of 66,000 psi.

   Can the Mauser you are looking at handle the .308 Winchester?   Consider this:  You are talking about a bolt action mauser, made more than 50 years ago by the Germans, specifically designed to handle the 8mm Mauser round (which is only about 46,000 psi).  Many of these rifles were bought surplus by Israel in a time of desperation after World War II and "converted" in the cheapest way possible to fire the 7.62 Nato round, and you want to fire a 66,000 psi hunting round in it, while your face is sitting one inch from the action.

  Not me brother.

 

[Luckyducker]

  I had an Ishapor rifle which is a Lee Enfield designed bolt action that were built in India chambered in 7.62 Nato and I fired 308Win ammo through it with no problems at all.  Military ammo is loaded to very high pressures, so high that sometimes the brass used for it is rendered useless to a reloader because it suffers head seperation after the first firing.  I don't think any commercially produced ammunition is loaded to this extreme. 

[Mikey]

Igm:  That Mauser should be strong enough to rebarrel to a magnum caliber.  The Isrealis took many wartime 8mm Mausers and converted tehm to the 7.62x51mm Nato round.  Mannyrock is correct - they are not the same round pressure-wise, just identically dimentional but, the 98 Mauser makes a excellent conversion to 308.

Just about the only problem I have ever read about with the 98 Mauser conversions to 308 is the ease with which you can chamber the rounds.  I guess you can get a bunch of stovepipes with the shorter 308 round (51mm as compared to 57mm) but, I think Brownells sells a magazine adapter or somesuch that allows for smooth chambering of the shorter 308 from a converted 57mm length magazine. 

Good luck and hth. 

[Dave in WV]

The 7.62x51 and the .308 can be interchanged safely.

[mannyrock]

      Mikey makes some good points.  Here is the problem:   Some 98 Mauser military actions, that are in really good shape, can be safely rebarrelled to .308 Winchester.    But, it depends TOTALLY on the condition of the particular action that you are talking about.  Some old actions have cracks in them, that can only be discovered by having a gunsmith "magnaflux" them.  Others may have deep pitting in them, that has cut down through the thick outer skin of the action, into the soft portion of the metal, resulting in weak spots in the action.  Others may have been built in Germany during the last few months of the war, when bombs were falling daily on the factories, and slave laborers were doing everything possible to sabetauge the rifles. Were they properly heat treated?  Who knows.

   So, to get a reliable 98 mauser military action to convert to .308, you have to have someone with lots of experience hand-select an action for you, and run a few basic tests on it.  You can't just grab any old mauser action, whether convereted by Israel or not, and say that it will be fine.

  And, even with a good military action, converted to .308 Winchester, lots of folks have found that after just 1,800 rounds or so, they start to experience "set-back", meaning slowly growing head space, again simply due to the fact that the metal used for these actions is not modern nickle-steel, but is instead an older softer carbon steel, with a thin tough skin on the outside, due to the heat treating process.
 
   As for your current Israeli Mauser, notice that the Israelis did not stamp ".308 Winchester" on the outside of the barrel.  They stamped "7.62."  That ought to tell you something.

   Mausers 98 are great actions.  But, you have to understand and appreciate what you are working with.

  I have had LOTS of experience in this area.

Best Regards,

Mannyrock


   

[mannyrock]

  Sorry for the typo in my last reply.  Alot of military mauser actions that are converted to .308 Winchester will start to show set back, and increased headspace, after as little as 800 rounds.

[lgm270]

Thanks for the informative and interesting post, Manny. I was not aware of the problems of set back and softened steel with re-barreled or otherwise converted military mausers.   You seem very well informed and experienced on this subject.  You introduced a new dimension to the issue of "7.62" vs. "308 Winchester."  

Even if  the rifle in question were a modern, state of the metallurgical art and engineering, the issue of the proper ammunition would still be of great importance.  

The rifle in question  was one of many thousands  re-barreled by the  Israelis from the original caliber to "7.62".

The 7.62/308 issue raises a number of questions.  Is it safe to re-load  boxer primed U.S. military mil-surp 7.62 brass with .308 dies for use in .308 rifles?

If, as I understand it, the 7.62 Nato is slightly longer than the .308,  then the 308 full length re-sizing die would cure this problem and, given due attention to the reduced power capacity of thicker walled mil-surp brass, 7.62 brass could be safely resized, re-loaded and used in .308 rifles.   Am I right on this?  

Also, I used to purchase  Winchester 7.62/308 "generic"  147 grain fmj  ammo for use in commercial .308 rifles.  There was never any reference that this ammo would be unsafe  or improper in 7.62 nato rifles.  Indeed, Winchester ammo boxes were labeld as "308. Winchester (7.62x51mm)" .  A photograph of a box of this product on the Midway website (see link) shows this still to be the case.

http://www.midwayusa.com/viewProduct/?productNumber=830685

I have had some bad experiences European and other mil-surp 7.62.  I think some of the South American stuff was badly over loaded a few years ago and I got some of it and it stuck in the chambers of my comm'l .308.   I promptly stopped using it and dumped it.

  

[mannyrock]

LGM,

    I do not handload, so I apologize that I cannot answer most of your questions about the 7.62 Nato vs. .308 Win in your last post.

    I can tell you this:

    1.  If you have a modern, nickle-steel or chrome-steel, sporting rifle specifically made for the .308 Winchester, then you can shoot U.S. military spec 7.62 Nato in it, with no problem.  The problem, however, is the one you experienced.  Lots of the surplus 7.62 Nato out there, such as the stuff from South America, was made with bad quality control, or was made intentionally "hot" for some reason, and can create high pressure in your rifle.  I too bought a sleeve of it, then had two rounds show unsafe pressure signs and get stuck in my rifle, and so got rid of all of the rest.

    2.  The ammo that you are talking about on the Midway site is correct, but a little tricky.  It says .308 Winchester (7.62 x 51 mm).  Since the external dimensions of the .308 Winchester are 7.62 x 51 mm, then this is correct.  But it does NOT SAY ".308 Winchester (7.62 NATO)."   The reason being, that these are not the same cartridge.     They have different load and pressure specifications.

     Since the boxes specifically say .308 Winchester, then I believe you must assume that they are loaded to .308 Winchester specs, which is 66,000 psi, and accordingly I would not be shooting them in any old military mauser that has been converted to 7.62 Nato, whether by Israel or anyone else.

    Some folks solve the dilemna by handloading the .308 Winchester rounds with very mild loads, with low pressure, that create a round a tad weaker than the .300 Savage (but fine for deer hunting).  I have not done this myself, but they apparently feel safe shooting the lower pressure load.   Again, it all depends on the exact quality and condition of the exact action, the exact bolt, the exact barrel, and the exact headspacing.

    Hope this helps some. 

Mannyrock

[mannyrock]

  One last point to remember:   After the creation of Israel, it was a bankrupt country, that had no money, trade or credit, that was constantly being attacked by three neighboring countries, and was absolutely fighting for its life! 

  Israel needed ANYTHING that would shoot! They bought up tens of thousands of abandoned, scrapped and surrendered Mausers that the Germans left lying around Europe.  After the invention and adoption of the 7.62 Nato round, the U.S. had tons of it at its disposal, and being the only major country that would give military support to Israel, it became clear to Israel that this is the only free ammo that would be shipped to it.  By the late 1950s, most modern machine guns were shooting the round as well.

   So Israel realized that it would have to have its rifles converted to 7.62 Nato.   They set up a factory in Israel, and the Israeli Defense Force ("I.D.A.") did lots of the conversions, on a shoe-string.  And, they also paid the FN factory in Belgium to do lots of the conversions.  (The FNs are considered to be the best of the conversions.)

   In short, Israel did not convert these 98 Mausers to 7.62 Nato because they thought they were creating a wonderful, strong, perfectly safe, infantry rifle.  They did it because they were desperate, and it was all they could afford!!!   
 
 Nuff said.

Manny

[Black Eagle]

I've built a lot of rifles on military Mausers and some very old military Mausers although I much prefer the new commercial Mauser actions. Most of the rifles imported to Israel were Czechoslovakian [CZ 24] rifles and they imported boatloads of them in 1948. Some were built by Fabrique Nationale in Herstal Belgium. Both of these are fine actions and will handle a .308 Win. with no problem. [I once opened the bolt face and built a .308 Norma Magnum on a CZ action. That Norma is still going strong after 20 years of hard use.] CZ and FN tended to mark their rifles on the lower left side of the receiver. You may have to remove it from the stock to see it. The ones you worry about are those built in Oberndorf, Germany after 1943 and those built in La Coruna, Spain. They tend to get locking lug set back and sometimes very quickly. I once barreled a La Coruna with a 6.5-06 just to see how long it would hold up. I had significant lug set-back in fewer than 50 rounds and detectable lug set-back within 10 rounds. You can draw and re-heat treat these actions but it is more expense than the actions are worth.

I know nothing about 7.62 NATO ammo. I haven't fired a round that I didn't handload myself in 45 years. However, the +P and +P+ ammo usually has thicker case walls and the reduction in case capacity increases pressures given the same powder charge. They may load the thicker cases in 7.62 NATO rounds way down in order to get adequate pressures and use less powder. Normally, you use the thicker case walls to increase pressures with lower powder charges. I used to have 100 +P .257 Roberts cases and they were thick walled and required about 10% less powder to reach standard case pressure and velocity levels. [I hated those cases and I trashed them. There was too much variation in them after fireforming.]  Nevertheless, why not take it to a gunsmith and have him check it out and test fire it with .308 Win ammo? He will be able to tell very quickly whether the action will hold up over time and he may test it at higher pressures than traditional factory ammo. [I always tested mine at pressures that most folks would call "excessive" and there is a way to do this without risking life and limb.] 

[mannyrock]

Black Eagle

   I agree that the action should be taken to a gunsmith for inspection and testing.  But, it has to be taken (or shipped) to a smith who spends his life converting and building mausers.  There are still a fair number of these folks around.

   The average gunsmith doesn't know squat about how to examine and test an old military mauser action.  They are absolutely clueless.

   Manny

[Skunk]

Good info Manny on all of your above posts.

[mannyrock]

   Thanks Skunk.   It took me about $3,000 of wasted money, and two years of frustration, to learn the things I have posted about the mausers.  I hope I can save other folks from the same fate.

    If someone really wants a custom rifle on a mauser military action, then they need to contact a true mauser-smith, and have him hand-select a military action for him.  The VZ-24s seem to be the most commonly selected these days.


Best Regards,

Mannyrock