That is very similar to the penguns that shoot flares. USAF pilots and crewmembers have them in their survival kits. The ammo looks a little bigger than the flares for those, but it works on the exact same idea. If it will shoot the flares, and you have a safe place to do so, I say try it out. It's pretty fun.
A hit with a .45 ACP beats a hit with a .22 LR everytime. A hit with a .22 LR beats a miss with a .50 BMG everytime.