Officers attended a property in Murray Street around 1pm on Monday, February 28.
Townsfolk were shocked when they saw police in full riot gear and carrying weapons in the street close to the centre of the town.
Uniformed officers and at least five police vehicles were also in attendance.
A Police Scotland spokesperson said: “Police received a report of a man in possession of a possible firearm within a property on Murray Street in Duns around 1pm on Monday, February 28, 2022.
“Officers attended and the weapon was identified as a toy gun.”
Commenting on a picture of the heavy police presence on social media, one observer wrote: “What on earth?? Guns in Duns?”