Reuseable Airsoft Grenade

I have been trying to make a compressed air grenade for a while. now i have come up with this.
The delay depends on the strength of the elastic band opening the valve. The balloon should inflate and pop sending out a spray of bbs (the flour is for effect). if you double up the balloon you will get a louder bang and maby a more power full spray. Making it all air tight is the hardest part.
to load fill the balloon with bbs and powder strech over the top of the ball valve screw on the modified hose connector. Set up the mecanism and presureise through the bicycle valve. I AM NOT RESBONSINLE FOR ANY DAMAGE CAUSED IN THE MAKING OF USING OF THIS INSTRUCTABLE!
materials:
330ml bottle
15mm ball valve
bicycle valve
spring or elastic band
hose connctor
a strip of metal for the handle
a piece of wire
a key ring
balloons
bb's 
flour or talcum powder
 tools:
tape
superglue
pliers
hack saw
maby a knife or drill to put a hole in the bottom of the bottle.