The 1875 or so FPS quoted by the OP is from a rifle. The short barrel of the mini will be even louder, as there will be more unburned powder contributing to the "BANG,". As previously mentioned: when using the mini for actual protection, that will be the least of you concerns. However, if the bad guy survives the bullet(s), remember he is in the path of the noise travel, getting slightly more of the noise, and depending on distance, a lot more of the pressure wave of the blast. I doubt it would be enough to inflict additional injury, it will at minimum be disconcerting for him.