If you have seen airsoft Claymore mines, you’ll know that they usually have a double mousetrap mechanism inside. Basically, the energy that propels the BBs is stored as tension in the springs. This is a simple mechanism that doesn’t require gas canisters.
Throwable grenades, on the other hand, use gas canisters as the propelling agent. Ideally you could use an electronic grenade, but some fields might not accept grenades that don’t shoot actual BBs.
Enter the Nuke ADG. This is a commercial product that successfully combines the spring mechanism and the grenade body. It has three windows to cover the full 360 degrees, and an optional attachment for mini-powder cartridges that make a loud bang on explosion.
While most reviewers agree that it has a durable and professional design, many say that it tends to break after a while. This goes to show how difficult it is to create such a mechanical system that is bound to hit the floor hard again and again.
Regardless, it is a very curious product which can serve as inspiration for anybody interested in spending less on CO2 refills.
[I am not affiliated with the creators or any retailers of the featured product, nor this is a sponsored post]