THE IDEA:
Pictures will be below

I have been designing this little project for a little while now and was hoping to gather some feed back about its practicality and to see if there was an actual want for such a product some time in the future. I have yet to make a prototype and I am still working out the materials that I am going to build the 40mm out of so by all means if you have suggestions feel free to make them I am totally open to Ideas. The grenade itself is designed to fit into either a mid to long sized grenade launcher (such as an M203) or a shoulder fired air powered rocket launcher. It must have an external source of propulsion (like a nerf rocket needs a gas 40mm shell) to be fired. The grenade is designed to be extremely light because of the risk of bodily harm on impact, for this reason the grenade is composed of light weight materials and features an airbag to cushion the impact (It also serves as the firing mechanism). On impact the air filled bag on the front of the grenade will compress causing an increase in pressure within the grenade. This pressure change will cause the bbs to be launched from all sides of the grenade. This design will be totally reusable and requires no re assembly other than the addition of new bbs. The cost I that I pan on building this grenade for will most likely be less than $20 a pice.
THE PROBLEMS:
My design has a few issues which need to be worked out.
1. The grenade is made out of rubber which tends to rub and create a great amount of friction when moving, this means that I need to coat the grenade in some sort of lubricant or material that will allow it to slide easily form the launcher. Right now my idea is a spandex outer sleeve.
2. Right now the only way to fire the grenade is with existing 40mm grenade this greatly reduces the potential barrel length that may be useable by the grenade (I need to find a better power source)
3. materials I need to find a rubber like material that is easy to form and relatively cheap.
Any and all ideas are appreciated
-DAN