They got shot down. But, and this was some crazy shit, they survived. 

But then the VC were all over the motherfuckin' jungle. Charlie liked souvenirs too.

Barnes knew the drill, he had it down cool with Bobby D; belt of ammo off his shoulder and loaded into the pig like clockwork, laying the belt in Bobby's hand even as he got the shotgun ready; but he didn't rack that, because that'd give them away.

The thing was, Bobby knew how to lay down the fire, but Barnes was his insurance policy, a guy that watched the other points to make sure Charlie, who was a motherfucker when it came to flanks and popping up outta nowhere, didn't just jump out of some bush screaming 'TIEN LIEN!' with a fixed bayonet or a burst from his AK. Bobby had his job, Buck had his; provide ammo, do security. Engage if anything pops up out of nowhere. The gameplan worked pretty well for the two, and the sarge apparently knew better than to split up the gig. 

So when it was time for Bobby to get the pig up, it was Barnes that popped around and let off a round with his shotgun at the first Cong he saw, then a second at the guy that looked like he was reacting to Bobby's Pig. The third? Well, that was another one at the same guy; he was fairly sure he got the dude, but he couldn't be entirely sure. He had a rhythm all of his own with that shotgun -- he never hurried, he didn't slam fire, but he could lay out the shots rapidly, and the shotgun always seemed to scare the VC. It was loud, and in a fight, loud had a psychological dimension all of its own.