Automatic "rifled cannon"

[Spuddy_boink]

So I was looking at potato cannons (I know suprising right!?) And I notices they aren't terribly accurate so I figured hey make it more accurate and shoot fully auto magic by making a trigger pulls that injects air and all into the chamber ignites that with a 0.12 second delay from when it was I injected then the igniter ignites it it would be 50 cal and "rifled" inducing spin on darts, similar to how a thrown football is stabilized by a spiral. This is achieved by using strings (like fishing line) or internal bearings within the barrel to frictionally impart a twist to the dart as it flies out. This rotation stabilizes the dart's flight, reducing "fishtailing" and making shots straighter and more accurate. 

[RileyJames]

Interesting idea, but that sounds like it could get complicated fast. Accuracy gains might be limited, and safety would be a big concern with anything automatic or ignition-based.