explosion effects

Hi everyone,

Might have an easy question here!. At present we are making a movie, and at some point in post production I will have to super impose an effect that simulates artillary shells hitting an embankment from a ship - with the resulting explosions.
I wonder if there is any generator out there for FCPX that might do the trick?. I have found a few video motions with alpha channels - although good, they don't look real enough for shells hitting the beach.

I would be happy with just videos of the explosions - we can do the rest :).

Any suggestions would be great...

Cheers,

Pete