The additional sessions judge also imposed a fine of Rs 5,000 each on Chothe and Surendra.
According to police, the duo shot Pradyumna dead in Margaya village as they nursed enmity against the victim.
Meanwhile, a man was handed seven-year jail term by another court for unnatural offence.
The chief judicial magistrate convicted Arvind and handed him the jail term, prosecution sources said.
The crime, involving a minor boy, had taken place at a lonely spot in Myasur village in August 27, 2011.