I think originally *Billboard *reserved the term for a record that had jumped either five or ten positions from the previous week. In other words a song could get a bullet, lose it, then get it back.
I’m certain there were other songs that reached #1 with a bullet, they just didn’t start there. Especially in the '60s, but also the '70s, singles were the best sellers, and linked tightly with radio airplay. During that time, #1 songs didn’t stay #1 for very long, because the teenagers ran out, bought the single, then did the same thing the next week with a different record. According to music historian Fred Bronson, Yesterday by the Beatles spent a total of just 11 weeks in the Top 100.