for Free-Fire Zone by Chris Lynch
Morris, Rudi, Ivan, and Beck are best friends for life. So when one of the teens is drafted into the Vietnam War, the others sign up, too. Although they each serve in a different branch, they are fighting the war together -- and they promise to do all they can to come home together. Rudi is perhaps the most concerned about whether or not he'll be able to keep that promise. After all -- and he'd be the first to admit this -- he's not the most capable guy. He's not smart like Beck, or brave like Ivan. He lacks the strength of Morris's moral convictions. But once Rudi is pulled kicking and screaming into the Marines, he at last finds something he's good at: following orders. Will that be enough to keep him alive? And if he does survive the war, will his best friends even recognize him on the other side?
Publisher description retrieved from Google Books.