Musket discharge test - file linked.

https://dl.dropbox.com/u/13211994/smokeParticles.blend

Hello,
Can anyone give me any idea on how to improve these particle test please?

It is going to be the muzzle discharge of a musket/blunderbuss, and looks a lot better in the viewport than it does when rendered. There is a particle system for sparks, and a smoke sim for the smoke. I’ve been tweaking away and don’t get why it looks different when I render a frame (or more).

cheers for looking.
Stuart