It was commonly assumed by users in the service that the term referred to a supposed 'buzzing' sound its darts made when flying through the air. The first example was the 105mm howitzer M546 anti-personnel tracer (APERS-T), first fired in combat in 1966 and thereafter used extensively in the Vietnam War.
It was widely assumed by users within the service that the term referred to a buzzing sound produced by its darts as they flew through the air. The first instance of this usage was observed with the M546 anti-personnel tracer (APERS-T) howitzer, which was deployed in combat for the first time in 1966 and subsequently used extensively during the Vietnam War.