Here is a cool rubber band gun from Japan. The text was translated (most of it makes sense).
Original non translated link.

“It is electromotive machine gun 2nd feature P211 tandem barrel II.
As for the 1st feature P203 tandem barrel receiving the change of design big it does again to load the gear box onto the midship production midway, it was the model which you complete. (At the beginning, it was the schedule which is loaded onto the frame rear section)
Furthermore because luxury and the difficulty that also mechanism adopts, change of semi [huruoto] is possible, it became very labor, but the excessiveness of change of design cursing, very much fragility becoming making spares.
Being breakdown tend, now object it converts either the opportunity which flaunts full automatic power without.
Those where you complete with the bone may break puts out also the fact that it repairs fairly well, rather the thing recreating [chi] [ya] obtaining are the latest model.”

Via: TechEBlog