Officers of fourth battalion of Assam Rifles held the man and seized three .22 mm pistols and as many magazines from him on August 19, the statement said.
The man was handed over to the officers of Champhai police station the next day, the statement said.
It was still unknown whether the arms were meant for north east insurgents, sources said.
Mizoram, which shares 722-km porous international border with Myanmar and Bangladesh, has been one of the biggest routes for arms and narcotics trafficking in India.