Axxe55
Retiretgtshit stirrer
Most of 9mm rounds are designed for pistol, so putting them through a 16" barrel may affect their performance. But I have to be honest, It is not a bad choice for home defense. The 556 and 762 could be overpowered for the urban environment. Those could penetrate the walls too easily.
Most pistol cartridges when used in rifle have an increase in velocity and energy.