Arms Assistance (Not Reselling, Self-Research of Arms, Transformation and Innovation)

I would like to read a book similar to "Bright Sword: I Climb Industry in the Rear Area". Modify firearms (not science fiction, don't use nuclear fusion or anything like that), change firearm accessories for mass production, develop and create by yourself, use your whimsical ideas (you can learn from I Love Inventions, rotorcraft modification