Spray of bullets. 
I thought about making up a little story about it being just a thinly-disguised Nazi secret weapon marketed to unsuspecting civilians, along with making up a cool German name for it like
Kugelspritzgewehr or
Sturmspritzer ('Bullet-spraying gun' or 'Assault sprayer'), but then I realized one of the DU halfwits that lurk here would probably take it as true and spread it all over place, which other idiots-at-large might actually believe and react to.