Military vs Homegrown

The only information I have is on the cartons of British produced MkVII.

Taken at the muzzle.

.308 Win. Norma Military Production 168 gr HPBT Match 

The other good reason to hand load is you have full control of the variables, like chamber pressure.  I decided I would not shoot .308 Win factory loads thru my DCRA, not knowing how close they are to .308 Win max pressures with the chamber/throat on my No. 4 7.62 conversions.  They are all probably fine, but no good reason to take the chance when you can handload. 

The claim that Norma is making that the diamond line (moly coated) bullets substantially increases barrel life is interesting. Barrel life is governed by throat erosion and that has a lot to do with powder burn temps and pressures. While the claim might be true in the sense that a one for one substitute of a plain jacketed bullet with a moly coated bullet keeping the same powder and charge weight would slightly lower pressures due to lower friction, bullets loaded to the same velocities seems unlikely there would be much difference in barrel life. 

NOS Enfield hammer forged heavy barrels for the L39/L42/Envoy must be very hard to find. But if the barrel life is truly doubled by substituting a plain jacketed bullet for a moly coated bullet, I would probably do that.  Alternatively, you can shoot reduced pressure loads for short to mid range work, save the “full” pressure loads for long range.  

Factory ammunition is usually loaded to magazine length.  You can substantially reduce pressures by seating bullets further out if the throat length allows it, which is the case for my DCRA 7.62 conversion.

 For 800, 900 and 1000 yards, I’m loading the Sierra 168 grain Tipped MatchKing (TMK) seated to a OAL of 2.95 inches, .020 inches off the lands.  Cramming that long bullet in the case to a 2.81 OAL reduces case volume significantly with a corresponding pressure increase.  I’m not seeing any load data specific for the TMKs, yet we know that when seated to the same length as the SMK, they must result in higher pressures for the same charge weight. 

The nice BSA barrel I shot out on that rifle had a very long throat, jump to the lands was over 0.5 inches.  I hadn’t shot any appreciable amount of cordite loads, but about 10,000 founds of NC powder. Your MLE could have that much throat erosion from the years shot with cordite.  A borescope pic would tell the tale. 

I have wondered if the rifling lead dimensions were changed after the Mk VII cartridge was introduced in new production barrels, but haven’t found anything to indicate this.  I suspect that the thinking was the rifle should be able to chamber and fire all previous marks of ammunition.