More than 1,000 armour-piercing machine gun rounds have been discovered buried in a field in Rackheath, near Norwich.
The unfired .50 calibre ammunition was found by members of an aviation heritage group on Tuesday, underneath a section of armour plating from a gun turret.
It is believed it could have been buried more than 70 years ago during the Second World War.
The ammunition was used in the gun turrets of American B-24 Liberator bombers, which flew from the former RAF Rackheath airbase.
Around 1,500 rounds - including tracer and fire-starting incendiary rounds - were discovered just three feet underground.
They were taken away later in the evening by the army bomb disposal unit from Colchester.
Trevor Hewitt, curator at the New Farm Aviation Heritage Museum in Frettenham, which was behind the search, said: 'They [members] came across a big chunk of metal which turned out to be the armoured plate from a gun turret, and underneath that they found the .50 calibre rounds.'
Mr Hewitt said the ammunition would have been used in the gun turret of a Liberator.
The American-made bombers, which flew from Rackheath as part of the United States Army Air Force 467th Bombardment Group, had ten .50 calibre guns on board.
Positioned around the aircraft in manually operated turrets, they would shoot down enemy fighter planes if they attempted to attack.
The chairman of the heritage group, who did not wish to be named, said some of the rounds were still attached to the original ammunition belts.
He said they had different coloured tips, which indicated whether the bullet was armour piercing or a tracer.
'I think someone must have just buried them rather than taking them home [to America],' he said. 'Because you can imagine the weight if it all had to be taken back on an aircraft.'
It is not the first time a Second World War artefact has been found in the area surrounding Rackheath.
In 2016, the wreckage of an American fighter plane was discovered along the route of the NDR in the village.
The P-51D Mustang belonged to First Lt Robert C Young, who lost control of his aircraft during an aerobatic display On April 22, 1945.
His plane, Ellie May, exploded on impact at Gazebo Farm to the west of New Rackheath.
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