The standard AR gun is a DI gas system. Some shooters don’t like corrosive milsurplus ammo through those type of systems because it blows the dirty leftovers all over the internals.
What you say is true, but retreading the article this is also a direct gas impingement action.
“What you say is true, but retreading the article this is also a direct gas impingement action.”
Maybe the special receiver it mentions protects the internals. I don’t know. I like piston guns. And I definitely won’t pay $1700 to shoot 7.62x39, 5.56mm, or 5.45x39mm.