The days are long and the years are short

The "Shot heard 'round the world" is a phrase that has come to represent several historical incidents throughout world history. The line is originally from the opening stanza of Ralph Waldo Emerson's "Concord Hymn" (1837), and referred to the beginning of the American Revolutionary War. Later, in Europe and the Commonwealth of Nations, the phrase became synonymous with the shot that killed Archduke Franz Ferdinand and plunged Europe into World War I.

From Wikipedia.

There is a also a reference to the shot from the cruiser Aurora that started the October revolution in Russia in 1917.

My take: all the other references occurred after the poem was written. So Concord and the American Revolution have the rights to the name.
 
The October Revolution already gets a catchphrase anyway: "Ten Days that Shook the World" from a book by John Reed.