That's not stupid to begin with, that was what it really was fluff wise. A repeating piece of artillery, working on similar principles as artillery, but with an effect closer to an autocannon. I guess the thought behind it was initially that you don't have autocannons above a certain size when it's not possible to scale it to such proportions, but you can try to get the same result with big artillery guns (close to medium size artillery) firing in quick repetition.
That was the same principles behind medium beams and pulses for example, that were actually small sized weaponry but so huge that it was using gimped medium sized weapons.
They sacrificed that on the altar of ergonomics, which I can understand, but that's a little sad to see though... They should have kept it in the item description or something;..