Rocket SMG

Rockets, such as those mounted inside a tube under a helicopter or on a Katyusha truck, have proven to be much more powerful than conventionally fired shells of the same size. It is my belief that this ratio could be effectivly miniturized to provide an SMG size weapon capable of delievering a projectile with power similar to the 20mm round. Advantages over conventional firearms; smaller than standard rifles, but exhibiting familiar features such as magazines, stocks, barrels. The rockets themselves would be about 12mm in diameter, 10cm in length. Unlike a bullet, sabot, or shell, the range is longer and straighter, as the rocket tends to drop off suddenly rather than gradually arcing downwards. The speed would be greater than the standard NATO 3,000 feet per second, which when coupled with a higher mass would result in much higher impact power. Also, using kinetic or explosive warheads would allow one to at least take apart light armored vehicles and "soft" targets. God I hate that term. The rockets would be fired via an electric prong at the base of the chamber, after being fed from a magazine. The disadvantages; though automatic or semi-automatic, the rate of fire could not be very fast, as the barrel would tend to overheat. The large size of the rockets themselves would limit the reasonable amount one might fit in a magazine to 10 or less. The complicity of the loading mechanism, though spring motivated, would have to be fairly complicated (what is called a "closed-bolt system") without the use of recoil energy. One might also object to having to haul high explosives around. I would like to note that I detest all things military but I did feel I needed to get this idea out, not as a weapon but as a half baked idea.