“Stoner MADE a piston drive prior to the AR”
And when he got around to making the AR, he decided against using it - I trust he’d do so for good reason.
“...he decided against using it - I trust he’d do so for good reason....”
And he did this one too:
http://en.wikipedia.org/wiki/Armalite_AR-18
Which had a gas piston.
Actually, I had the time line wrong (my apologies); the AR direct impingement came right before the piston-drive Stoner 63. So he tried a course correction, evidently.