Acting on a tip-off about the presence of several Maoists, police, led by SP Navin Kumar, recovered the huge cache of arms during operation "Green Hunt", Jamui SP Jitendera Rana said.
Materials used for making bombs have been recovered along with live pipe bombs, he said.
The Maoists, however, managed to flee. An exchange of fire between security forces and the ultras took place before the cache of arms was recovered in Harni jungle area, the SP said.
In 2005, the then SP K C Surendra Babu and six other other policemen were killed in a landmine attack by the Maoists in the same Bheem Bandh forest area.