When a Gun Nerd is Reincarnated to a World of Magic, He established a Harem army with Modern Weapons!?

Houta Youta, 27 years old, was a virgin, a high school dropout, and a former hikikomori. His life had been pretty horrible since his high school years and now, on his way home from work at the metalworking factory, he gets stabbed to death by a drug addict. However, it seems that he has been reborn in a fantasy world. (Source: Re:Translations)