Seen these on YouTube, and to be honest I thought they sounded cracker, they are a 3'1/2" case and they are.something like 1700 fps.
But I think that would be-
1.quite expensive
2. Hard to come by
But has anyone used them before
Link to the video, hope it works.http://m.youtube.com/#/watch?v=l5fSh8pzSeI