Finally My 1st Garand

[oldfoneguy]

The M14/M1A uses the White gas system patented in the 1930s. It had a less violent recoil and was easier on the parts. Garand was well aware of it but rejected it because the early versions were temperature sensitive whereas his direct system always worked.

Well how about that. Learned something new today, thanks Bob. No I was not aware of that but I am now.
So that's the reason the op rods damage when the wrong ammo is used. Direct exposure to the excess pressure.