I got an idea one day when I saw a company called Tannerite demoing one of their canisters online.
So one day I got down to trying to manufacture really sensitive "tannerite" using a 70:40 AP:AN ratio packed moist into large sheets of high density paper.

These proved to be sensitive enough to be used for .22LR at 120yards.
upto 400grams were used for long range targets.. I got quite a crowd at a local range wanting to shoot them. :D It was a blast!

Anyway, one downside to using AP is the needing to pack it moist due to problems with its high sensitivity when it is dry especially when the ambient air temp is high.

Now, reading further... I am hearing quite a bit about AN with Al powder being a good mix for a dry version.. ? Anyone tried it ? It needs to be set of with a supersonic shockwave doesn't it?

I am hearing quite a bit about AN with Al powder being a good mix for a dry version

That remains to be experienced ;)

Place one gram of ETN on a sheet of paper, spread it out aproximatly 1-1/2" square, and fold the paper into a small envelop. Tape this to a solid backing, and it will give a nice bang when struck by a .22. It works out to 40 yards; I haven't tested it beyond this range.

I got a video of some guy who detonated AN with Al on yahoo.com.Try this link:
http://video.yahoo.com/video/search?p=ammonium+nitrate&x=23&y=17

People stay on topic... if we are talking about pyrotechnic we aren't talking about detonation.
And this topic have been already discussed in Other explosives:

Tannerite Exploding Targets
http://www.roguesci.org/theforum/other-explosives/294-tannerite-exploding-targets.html
Exploding Targets
http://www.roguesci.org/theforum/other-explosives/3772-exploding-targets.html

I'm thinking they should definatley be merged into one big exploding target topic.