Officers at Woden Police Station were surprised when they were handed a World War I era pistol this week.
An elderly man attended the station on Wednesday and voluntarily surrendered the firearm, estimated to be 108 years old.
It will be assessed for historical value or disposed of safely, police said.
People who have an unregistered firearm or firearm-related items can surrender them to police without penalty, for registration, sale or destruction, under the National Firearms Amnesty.
Firearms can be surrendered to ACT Firearms Registry at 86 Vicars Street Mitchell.
More information on appointments is available on the Firearms page, however if you are unable to bring a firearm in yourself, you can contact the ACT Firearms Registry (02 5126 9076) to organise collection.
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