tim,

You're not going to like the cost! It's about double what black is!

Triple 7 at my local place is around 30 quid a tub, which is 1lb.

Use it by volume. Still loads of smoke. A bit "hotter" than black, so it goes off with a sharper report and a snappier recoil. Clean up is a piece of pi$$, just cold running water.

Give it a yaror two and you'll not be able to get black powder, full stop. The health and safety nazis will literally price it out of existance.