stacker grenade

grabcad

I have no idea how to operate this thing - it doesn't come with instructions and I'm not even sure where to start. The pin or ignition system is completely foreign to me, and when I try to figure out how it works, I get nowhere. It's just a model, after all, so I'm not expecting it to function perfectly in real life. However, this particular model has a "lock grip" feature that seems to be causing more problems than solutions.