At one time, a rifle shot or two would have been used as a signal.

Less than ten minutes had gone by when Helen heard a rifle shot.

The rifle shot was a million times louder than anything ever heard in the world before.

He began his finish with a question that cut through the air like a rifle shot.

He had, several days past, while hunting far to the east, heard a rifle shot.

This time the sound of the rifle shot came afterward.

She never heard the rifle shot, for the bullet arrived before the sound.

A single rifle shot sounded from the head of the column.

My feet hit the sand as a rifle shot fired.

Only the lack of rifle shots made this "time" different from those times before.