http://news.bbc.co.uk/1/hi/world/americas/3324893.stm

I wonder if I could use it in an IPSC match ...... ?

I recall reading some info on a german WW2 device for shooting around corners. It was just a bent barrel!! I think they had two versions, one of 30degrees and maybe a 45degree one. Not sure how effective it was but as far as I know it was a legitimate invention.