Ah well distance depends on high how your horse is, how high they jump the fence and how far you are willing to lean out!

The ideal shot is behind the horse, so the blast is behind them.

What I am after is someone who knows their powders and can advise on the quietest ( possibly the worst?) - otherwise going to cost me a lot in trial and error!

I don't often get as close as this guy, as he has longer arms and both horse and rider have been doing it longer than me!!
http://www.yorkshirepost.co.uk/webim...2414527502.jpg