Bruce Windorski could hear Islamic State fighters taunting him as he peered down the moonlit Syrian village street early this year. Their voices were getting louder, and their aim seemed to be getting better.

The 40-year-old former Army Ranger from Wisconsin reached into his bag of semi-reliable grenades, chose one, pulled the pin and tossed it over the wall. There was a blast, he says, and the jeers came to an abrupt halt. “It was definitely a satisfying event.”

But the battle continued for days. As militants closed in one night, Jamie Lane, a Marine combat veteran who had traveled from California to fight, wondered if they would make it out alive. “We’re holding our ground,” he says quietly in a video he took in the pitch dark as gunfire crackles. “I imagine it will go until dawn.”

The men are part of an unusual fringe of American veterans joining the war against Islamic State. They go, even as their president and Pentagon leaders strive to keep U.S. forces out of the ground war.