Chingsianpianga, 36, was arrested during a joint operation by Mizoram Police and Assam Rifles troopers at Hnahlan village in Champhai district on Friday night when he was smuggling the arms into India from Myanmar across the IB.
Two M-3 rifles, three loaded magazines and a huge cache of bullets have been seized from him, a police officer said.
The officer said Chingsianpianga was a resident of Darkhai village in Myanmar.
The arrested man told police that the arms were smuggled from Myanmar.
"The seized arms and ammunition were suspected to have been meant for Chakma rebels operating in Bangladesh," the officer said.
The Chakma rebels have been demanding sovereign status in Bangladesh's Chittagong Hill Tracts.
Mizoram shares a 510-km mountainous border with Myanmar. Assam Rifles troopers were posted along the 1,643-km India-Myanmar border along Arunachal Pradesh (520 km), Manipur (398 km), Nagaland (215 km) and Mizoram (510 km).
Mizoram also shares an unfenced 318-km international border with Bangladesh.