Officers contacted 40-year old Juan Romo-Bais in the area of Highway 99 and Kern Street after receiving a shotspotter activation shortly before midnight on Sunday.
Officers found Romo-Bais with a total of six loaded zip guns he made himself.
Five of the six were manufactured to hold and discharge .22 caliber ammunition and one was manufactured to hold and discharge 12-gauge shotgun ammunition.
Romo-Bais was arrested and booked into the Fresno County jail for several felony weapons charges.