Fifteen bullets were taken from a museum and destroyed after they were found to be still live.
Their cartridges were found to contain explosive during an audit carried out by the army at Lynn Museum.
A report to councillors said ordnance kept in Norfolk museums was inspected by a soldier from Merville Barracks, Colchester, to ensure it was safe.
It said any ammunition in collections must be certified free of explosives.
"At the time of the visit, some items were found to contain explosives and as such, it was not possible to be issued with a certificate for these items," it said. "Due to the nature of this audit, and small scale of these objects they were removed immediately by Sgt Heydon and taken to
Army Melville Barracks Colchester for immediate safe disposal."
The report says the 15 German cartridges were in a glass display case in the museum's stores.
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