The Armourer wrote: Had you considered that commercial 308 cases are very different specification to 7,62 NATO spec cases ? Case wall thickness is much thicker on the 7.62 compared to 308 7.62 chambers are 13 thou (0.013") longer than 308 meaning that these thin-walled 308 cases stretch and can split. The case volume on a 308 is greater than a 7,62 leading to different powder burning characteristics (*Throw in a 'bit of extra powder' and you have an accident waiting to happen.*)

Let us address that last comment made by The Armourer first and foremost shall we.

For those Brand New to and starting out in the reloading world. NEVER under ANY circumstances just "Throw in a bit of extra powder."

The Armourer. Yes, the .308W is not entirely identical to the 7.62x51mm NATO, owing to differences in tolerances; (Mainly meaning that the differences are in the actual .308W & 7.62 rifles chambers respectively) and therfore, some commercial rifles will not handle military ammunition.

However and be that as it may. Even with the differences in case wall thickness/case volume between commercial and military brass respectively, as long as the reloader stays well within the published guidelines of his or hers chosen reloading data and NEVER exceeding the max charge weights, reloading for the 7.62x51mm NATO chambered rifle using .308W commercial brass and using projectiles of 175grn's or less, (cartridge capacity and overall cartridge case length are not well suited using projectiles exceeding 180grn's) should be of absolutely no issue or consequence to the rifle or its user. It is ONLY when a reloader goes against what is recommended that an issue will undoubtedly arise. 

Food for thought Alan: Once a commercial .308W cartridge case has been fired in a 7.62x51mm NATO chambered rifle, that particular cartridge case is no longer to the .308W commercial rifles chambers specifications is it not and no longer having the potential issues of stretching or splitting?...

We have hashed this one out several times.  But, here's my view, FWIW.

You may well get into trouble if you load your LE 7.62 with max .308 Win published powder charges using 7.62 military brass. I certainly wouldn't do it, that goes against reloading manuals that recommend reducing the charge when using military 7.62 brass.  Remember, the No. 4 action was designed for the .303 British cartridge, not the .308/7.62.  It turned out that it had sufficient strength margin to handle the higher pressure 7.62 NATO round.  

My last thought is about the long term wear/tear on the action and barrel.  You will be better off loading the LE 7.62 to .303 British pressures.  

  

Sidenote: The published data that can be found throughout the internet legally and through Public Domain lists The United States Military's M852 Match Cartridge of having a chamber pressure of 50,000 PSI using their testing process and a pressure of 44,683 using the Copper Units of Pressure tests. Again. All well below that 45,000 CUP number...

The 7.62 case base diameter is slightly larger than the .303, which gives slightly higher bolts loads at the same chamber pressure; but not enough to worry about unless your near the maximum. 

Not sure I would call 44,683 CUP "well below" 45,000 CUP, but no risk there.  

Interpolating Hodgdon Reloading Data, my VARGET Match Loads (rounded to the nearest 100 CUP):

   .303 - 40 gr, 174 SMK, 41,000 CUP   

   7.62 - 40 gr, 168 SMK, 37,000 CUP (estimate 3,000 CUP higher with 7.62 brass) 

   7.62 - 43 gr, 175 SMK, 44,600 CUP (for 800 to 1000 yard line limited use, commercial .308 brass)

The two 7.62/.308 40 grain Varget load is actually a bit under the .308 minimum charge, but this still gives fairly good load density in .308 cases, so I'm not concerned. 

I would consider the 40 grain Varget loads as "maximum" for high volume use in the No. 4 rifles.  For the .303, I've probably shot in excess of 8,000 rounds of this load in my No. 4 I use for shooting CMP matches, and another few thousand in the other No. 4 rifles I have.  No issues at all, no measurable change in headspace, very good accuracy.  

  

Taken from a dedicated On-line source:

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