"It is the second time in three years that a mini-gun factory was discovered in the house of the same accused, Usman Mian," Superintendent of Police Prabhat Kumar said.
In all, 51 incomplete pistols, magazines, 55 gun-barrels, four machines, cutters and several other materials were recovered following a raid in the house under Margomunda police station, he said.
He indicated that the weapons manufactured there were being supplied to Maoist ultras as the seized arms matched with those found with the red rebels.
While Usman belonged to Deoghar, most of the other accused belong to Munger district of Bihar.