Cold barrel zero / Matthew Quirk.

Enhanced descriptions from Syndetics:

John Hayes is a Special Operations legend who went rogue on a deep-cover mission and betrayed his own soldiers. Disgraced and on the run, he returns to the United States to get back to his wife and daughter and take revenge on his accusers with a series of devastating attacks.

Only one man can stop him: Thomas Byrne. He once fought alongside Hayes as a combat medic, but he gave up the gun. Now a surgeon, he moves from town to town, trying to forget his past, until he is called upon by a high-ranking government official to help capture the man he once called a friend. Hayes and Byrne were once as close as brothers, but with the fate of the nation hanging in the balance and nothing as it seems, both men must decide whom to trust -- and whom to betray.

In a final, explosive battle for justice, they face off along a rifle's cold barrel. Cold Barrel Zero brings together the blistering pace of Lee Child, the nonstop action of Brad Thor, and the richly drawn characters and moral stakes of Daniel Silva. An experienced reporter armed with deep behind-the-scenes research into America's Special Operations Forces, Quirk takes the military thriller to a new level of suspense.

Reviews provided by Syndetics

Library Journal Review

Quirk (The Directive) here introduces listeners to John Hayes and Thomas Byrne, two former special operatives currently working outside the system. Hayes went rogue on a mission and is being tracked down by the U.S. government, and Byrne is a surgeon hunted by someone he couldn't save. These two men were once friends and brothers in arms and now watch each other with caution. With the fate of the United States in the balance, will they outmaneuver the foreign spymaster who is really pulling the strings? The plot is solid, but the characters could have been fleshed out a bit more. Peter Coleman's narration is well done. VERDICT Recommended for fans of the author and spy thrillers in general. ["Highly recommended for fans of rapid action with down-to-the-wire conclusions": LJ 2/15/16 starred review of the Mulholland: Little, Brown hc.]-Scott R. -DiMarco, Mansfield Univ. of -Pennsylvania © Copyright 2016. Library Journals LLC, a wholly owned subsidiary of Media Source, Inc. No redistribution permitted.

Publishers Weekly Review

Thriller Award-winner Quirk (The 500) goes flat-out explosive in this superior military adventure novel. Ex-Marine John Hayes has assembled a team of special ops agents who have been put on a U.S. government kill list by mistake. In an effort to obtain evidence that will exonerate them, they pull off a spectacular armored car hijacking, seizing a mysterious 1,300-pound crate shipped from the Emirates to Los Angeles. Meanwhile, Thomas Byrne, a former combat medic who served with Hayes, is vacationing in Southern California when he's arrested on trumped-up charges and brought to meet Colonel Riggs, who's in charge of the military task force to capture Hayes. Byrne has no idea whether to trust Riggs or his old buddy Hayes, with whom he later connects. The explanation for all the mayhem rests in a war crime that Hayes supposedly committed, but as usual with this author, facts are slippery and doubts abound. There's plenty of cool cutting-edge technology, but in the end it comes down to action, and the riveting battle scenes are among the best in the business. Readers will look forward to seeing more of the skilled and deadly John Hayes. Agent: Shawn Coyne, Endeavor Agency. (Mar.) © Copyright PWxyz, LLC. All rights reserved.

Booklist Review

*Starred Review* With the safety of the country at stake, a band of highly skilled American operatives is up against the forces of the U.S. government, and Tom Byrne is caught in the middle. Byrne a doctor and former marine corpsman who had saved the life of Hayes, the leader of the operatives, on the battlefield is apprehended while on vacation in Southern California with his girlfriend, and recruited to help get Hayes, who was said to be responsible for a massive massacre of civilians in a foreign land. But Hayes tells Byrne a different story, in which Hayes is blamed to cover up for a senior officer who watched as terrorists executed villagers. Convinced of the innocence of Hayes, who has become a legend in black ops, Byrne joins his group of men and women in a deadly high-stakes, high-tech chase on land and sea. Quirk, whose two previous novels centered on corruption in the corporate world, spins an adrenaline-fueled, military-based action adventure just as skillfully. Characters, most known only by their last names, are well drawn and motivated, and their exploits are hair raising. Another hard-to-put-down adventure from Quirk, this is even more chilling for its air of plausibility. A fine thriller--Leber, Michele Copyright 2015 Booklist

Kirkus Book Review

Former combat medic Tom Byrne finds himself in the ultimate squeeze when he's caught between the FBI, which falsely arrests him for stealing government secrets, and a Special Ops veteran he once fought with who's accused of committing terrorist acts. Threatened and cajoled by both sides, who should Byrne trust? Hayes, the man behind the shocking theft of intelligence files containing the cover identities of every U.S. operative in the field? He swears to his old friend Byrne that he's only acting to clear his name. Or Riggs, leader of a government task force that says Hayes was responsible for a massacre of women and children in Afghanistan and now is putting the U.S. at grave risk of a terrorist attack? More than 10 years after returning home from the war, Byrne is still recovering from the guilt of "los[ing] myself in the killing when I should have been saving lives." Now he has to survive a deadly contest of wills involving drone attacks, fierce car chases and boat getaways, secret codes, a female martyr who may or may not be fake, and frozen bank accounts (his). Quirk, author of a pair of so-so urban thrillers involving callow protagonists (The Directive, 2014, etc.), takes a major step forward with this far more sophisticated effort. The story is expertly stripped down, the action relentless, and the characters multilayered. Having Byrne narrate his sections while everything else is told in the third person is a bit awkward, but Quirk makes it work. A lethal game of cat and mouse fuels Quirk's third and best novel, a military spy thriller in which one all-out conspiracy is met by another. Copyright Kirkus Reviews, used with permission.