If nothing good ever came of guns.... I beg to differ. Backtrack to muskets, which later evolved single shot rifles followed by semiautomatic and automatic weapons. Further use in wars, resulting in a partially related nuclear weapon development, resulting in nuclear power plants and power you're using right now to post this.
Simply put: war causes technology advances. Look at WW1: first use of airplanes in combat, which evolved from initially being scout vessels to dropping mustard gas to fighters, to early bombers. Forward to WW2, and we have advanced prop fighters and bombers (did I mention the B29 had computer controlled remote gun turrets?). Germans were experimenting with V1 and V2 guided rockets, and had first functional jet (ME-262) and rocket (ME-163A) fighters.
Without war, and without guns, we wouldn't be where we are today.