Complex sentence: "Minigun" refers to a specific model of weapon, originally produced by General Electric, but the term "minigun" has popularly come to refer to any externally powered Gatling gun of rifle caliber.
Split into simpler sentences: Minigun refers to a specific model of weapon, originally produced by General Electric. But the term "minigun" has popularly come to refer to any externally powered Gatling gun of rifle caliber.