The other convicts are -- Safiul Alam Saddam, 22, Abu Nayeem, 25, and Ali Hossain, 20.
The court of Lalmonirhat District and Sessions Judge Mizanur Rahman of Special Tribunal-1 delivered the sentence.
The court also fined the five convicts Tk 5,000 each, in default, to serve in jail for another six months.
Lalmonirhat court police sub-inspector (SI) Musa Alam said a team of Rapid Action Battalion (RAB)-13 of Rangpur detained the five ABT men after conducting a drive at a house in Kaliganj upazila of Lalmonirhat on 30 October in 2018.
During the drive, the RAB members seized foreign pistols, magazines, firing pins, detonators and bullets from the possession of the ABT men.
On the following day, a case was filed at the Kaliganj police station against the detainees.