Checking out these recordings I think the shots are firing at a humanly impossible rate. Either that or they were done at a very reduced FPS rate.(posted 9467 days ago)However, as per Krools comment on the 1943 recording, the fact that once he obtained auto-fire it did not continually fire smoothly - which it does if you hold the fire button down - I suspect it's either solely autofire or a combination of auto-fire and reduced FPS. Everyone I know back in the days when Star Force was big always held the button down once they had obtained auto-fire.
Cheers, BeeJay.