I recall a post on one of the benchrest boards about downrange accuracy.
The shooter had one of the Oehler accoustic targets set at 100 yards and a regular target at 334 yards. He said that in no case was a group at 334 tighter in MOA than at 100.
The corkscrew diagrams in the nennstiel papers are deceptive. They show the yaw of the axis of the bullet, not some sort of orbit around the line of fire. The NRA once figured that the air spiral of a .30 bullet was a maximum of .1". This might get you an oval hole in a near target before it damps out, but there is no restoring force to bring a bullet back towards the center of a group shot with other bullets.