Royal Marines caused panic at a national park after losing a deadly assault rifle during drills in Dartmoor.
Chiefs called off the exercise and ordered a widespread search for the SA80 automatic rifle.
However, the commandos were forced to alert Devon and Cornwall police after they failed to recover the gun.
The weapon remains missing.
Chiefs called off the exercise and ordered a widespread search for the SA80 automatic rifle
PA
“Losing your weapon is one of the worst things a marine or a soldier can do," a source told The Sun.
“The worst case scenario is this gun falls into criminal hands.
“It could be found by a rambler or even by kids on a wilderness walk.”
The source added: “These were marines competing for a promotion.
"It is really embarrassing.”
It was the first time a working assault rifle has been lost or stolen for more than two years.
Since 2020, at least eight guns have been lost or stolen, including two working machine guns.
The MoD confirmed it lost a deactivated AK47 assault rifle, a GPMG machine gun and a Glock X43 pistol last year.
Since 2020, at least eight guns have been lost or stolen, including two working machine guns
PA
The SA80 is the armed forces’ standard issue rifle and can shoot over 400 metres.
It fires .556 calibre ammunition at a speed of 940 metres per second.
The Royal Navy confirmed: “We are investigating an incident related to the loss of an unloaded rifle by the Commando Training Centre Royal Marines.”
