Rocket Launcher

So,
My friend and I have been experimenting with different "Rocket Launcher" type weapons.
Heres what we've tried so far:
-Aerosol Ignition (FAILED)
-Spring (SUCEEDED, BUT NOT WELL)
So our newest idea:
Butane "Rockets"
I shall explain. The idea came from my dad after looking at our Aerosol cannon, and I have sense perfected it. First of all, the actual launcher is a 2.5' x 3" PVC pipe. Attached to it is a fore grip, as well as a rest for your shoulder. Inside the foregrip, there is a BBQ Igniter that is wired to the back. About 2-3" inside the back of the tube is a pin with a plate across it, and the end of the igniter extending from the plate (The plate does not extend the full diameter of the barrel. Diameter will be 2" to allow a 1/2" of free space). The actual ignition "Chamber" is inside the 'rocket'. The rocket is a small piece of PVC, capped on both ends, and covered in expanding foam. On the end protruding from the back of the rocket, there is a small hole, and a Butane refill thing apoxied into the base. In order to get the rocket to fire, you cover the hole with something that can be broken or punched out easily (Plastic Wrap, etc.). You then fill the chamber with butane. The launcher is muzzle-loading, so you drop the rocket down the barrel. When it hits the plate with the igniter prodruding from the end, it will (in theory) penetrate the object covering the hole. Then, with only a click, the rocket will be ignited, propelling it out of the barrel (Aided by the plate giving the exaust something to push against). So, its not really a rocket, as much as its just a Bazooka type weapon. This is a project that Im hoping to start tomarrow, and finish next weekend. Questions, Suggestions, etc.?

dangerous much?
what happens when it hits someone? <you Them>

Hehe. Probably not going to be used on players, more so vehicles. Well, at least until I can find a good way to make a "High Explosive" round XD