Everything you read about not shooting .308 ammo in the 7.62 is based on the misconception on the changeover from CUP to the PSI transducer method of pressure readings 52,000 CUP is approximately 62,000 PSI which leads to mass confusion.
It is perfectly safe to shoot and interchange .308 and 7.62 ammunition.
(we did it with the 30-06 all the time and NO one complained)
The military 7.62 cases are thicker in the web area than the .308 to be able to withstand the greater headspace and chamber diameters of military chambers, which reduces the amount of reloads in the commercial cases and increases the chance of distorted banana shaped cases which has an averse affect on bullet alignment and accuracy.
I have fired three different types of commercial ammunition in my 2A1 and the only thing that was stressed was the commercial cases and not the rifle, the commercial cases would stretch and thin in the web area just like our .303 cases do.
Look at the pressure readings on the two reloading charts below for IMR-4350 powder in CUP and PSI 44,200 CUP verses 55,100 PSI, this is why you see information saying the .308 has much higher pressures simply because people do not understand the difference in the two type pressures. (P) PSI (C) CUP (with the exact same amount of powder)
As you can see below it is perfectly safe to put 32 pounds of air in your tires BUT if you put 220 kPa in your tires they will blow up and kill every one in a 50 yard radius. (And Santa still brings my Christmas presents)
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