So, a recent discussion on M1 Garand-specific ammo got me thinking about gas operating systems in firearms. The reason I had been told that Garands either needed specific ammo or an adjustable gas plug to avoid damaging their op rods was because modern ammo used powders optimized for heavier bullets in longer barrels, i.e. a slower burn rate. This, it was said, maintained higher barrel pressures for a longer time, putting more stress on the Garand's gas system than it was designed for.
And that made sense to me. I don't know much about internal ballistics, but spreading the pressure out