Rose Soldier

(from ebookjapan):

Red Transport used to be a first-class transportation company, but now it is a shadow of its former self. It has been taken over by the dastardly Sora Konzern, which has even brought the police to its knees!

The fierce members of the Red Clan stand up to avenge their grudge and plan a surprise attack on an Arab oil-producing country that is effectively controlled and debased by Kukon. They train like guerrillas with firearms stolen from the U.S. military, but then a Kukon helicopter arrives and unleashes a relentless barrage of bullets--!!