Trap shooting was designed as practice for hunting birds, and I always assumed that (and sport) was all it was ever used for. However, turns out that in WWI, the US Army found a very different use for skilled trap shooters: http://en.wikipedia.org/wiki/Winchester_Model_1897 Williamson, Harold F. (1952). Winchester (1st ed.). Washington DC: Combat Forces. pp. 158–159. So there you go, trap shooting has battlefield application
It's good to know that I've been training for something that is so cool and yet never even realised I was doing it.