Yes, as with the M1 Garand: Long in development, with contributions from many. Wasn’t the idea of drilling a hole into the bore to tap the energy of expanding powder gases first used by Browning in his “potato digger” 1895 machine gun?
IIRC Maxim was the first American to file patents on gas action. He made some gas action prototypes before deciding to go recoil action on his famous machinegun.
To the best of my recollection, I think Browning's potato digger was the first
practical use of gas action...but I could be wrong.
