COMBAT OUTPOST WILDERNESS, Afghanistan—For weeks, the fierce duel playing out in the mountains of eastern Afghanistan between U.S. and insurgent artillery crews had been decidedly one-sided—deadly only for the Taliban.

With better training and high-tech equipment, the Americans were so fast and accurate with return fire that shooting a mortar or rocket at them from the mountainsides overlooking their camp was practically suicidal.

The U.S. artillery platoon at Camp Wilderness killed 27 enemy fighters in the weeks before Aug. 11, while suffering no casualties of its own.

But a seemingly endless supply of insurgents replaced those they killed. The incoming fire continued. Finally a Taliban rocket found its mark.

Combat Outpost Wilderness sits in Paktia province in the heart of what the American military has dubbed the K-G Pass. It’s a gap in the rugged mountains of eastern Afghanistan that eases travel between Khost province and the Paktia capital, Gardez.

The area is home to several dozen U.S. soldiers of Gunfighter Company of the 1st Battalion of the 506th Regiment and a platoon of the 320th Field Artillery Regiment, all members of the 101st Airborne Division from Fort Campbell, Ky.

The pass has a dark history for foreign troops.

It was one of the most frequent sites of mujahedeen attacks on Soviet convoys during the Soviet-Afghan war in the 1980s. One of the most famous fights of that conflict, the Battle for Hill 3234, took place just a few miles away from Wilderness. All but five of the 39 men in a Soviet airborne unit were killed or wounded, though they held off an estimated 200-plus attackers, reputedly including Pakistani troops.

The spot is dangerous in the current war for some of the same reasons it was for the Soviets. It’s so close to the border that the Taliban can easily send in replacement fighters from refuges in nearby Pakistani cities and villages, making for a seemingly endless supply of reinforcements.

During a re-enlistment and awards ceremony Aug. 10, battalion Command Sgt. Maj. Franklin Velez warned the company what such a drawn-out duel could mean.

“You have been lucky so far,” he said. “But remember, it only takes one lucky round.”

Luck.

That’s what every soldier in Afghanistan thinks about while dashing for a bunker at the whistle of an incoming mortar round or the sizzle of a rocket.

Will my luck hold? What are my odds? Are the bad guys lucky this time?

Taliban “indirect fire”—rockets or mortar shells that arc to a target—is notoriously inaccurate. But enough rounds fall that eventually some find their mark, even among the most wildly fired salvos lobbed onto vast bases such as Bagram Airfield.

And they’d been hitting Combat Outpost Wilderness almost daily for a month, often several times a day.

The same day that Velez issued his warning, the commander of the artillery platoon, 1st Lt. John Orosz, 2nd Lt. Calen Lambert of Laurel, Miss., Staff Sgt. Octavio Herrera and several other soldiers hiked up a hill overlooking the camp for a lunch meeting with members of an Afghan National Army artillery unit.

The U.S. artillerymen had been training Afghans, and were proud of the results. The Americans brought sodas and water, the Afghans supplied traditional flatbread and tea. Together they talked about upcoming training sessions.

Herrera, a former field hand and United Parcel Service worker from Caldwell, Idaho, had two previous Afghan deployments under his belt. He pushed his sunglasses on top of his crew cut at a jaunty angle.

Just a year earlier, Lambert had been a college student studying abroad in Spain. Now he occupied a spot at the end of the makeshift table beside Herrera.

The mood was jovial.

“You don’t want to be near me when the rockets hit,” said one. “They usually land right next to me.”

“Yeah, don’t be near him when we have incoming,” said another. “For some reason, he always ends up exposed somewhere away from a bunker.”

Mostly, though, it had been the other way around. The Americans typically caught the insurgents in the open. In the previous weeks, the artillery platoon under Orosz’s command had fired more than 600 rounds at Taliban positions in the mountains surrounding the Wilderness outpost, killing their opposite numbers time and again.

In the company’s operations center, Sgt. Matthew Davidson watched video clips retrieved from the camera of an insurgent who’d been killed by indirect fire from Camp Wilderness. Taliban fighters slipping in from Pakistan often film their attacks so they can prove their deeds back home to get paid.

One clip showed the impact of the incoming American mortar rounds. As the insurgents are killed off-screen, the camera eerily continues rolling.

Yet another video left Davidson worried. It showed an insurgent calmly readjusting the sight and range of the mortar after each shot and jotting down notes.

The enemy, he saw, was learning.

American casualties have fallen to some of the lowest levels of the war as the U.S.-led coalition draws down in preparation for ending its combat mission next year.

The Afghan security forces are in the lead for combat nearly everywhere, and most American troops are now stationed on large, heavily fortified bases, training their Afghan counterparts and preparing to go home.

Last month, 14 U.S. service members were killed in action in the country. That was the lowest number for any July in eight years.

Wilderness, though, is one of the last places where U.S. troops engage directly with the insurgents. All that incoming fire means the American soldiers there face some of the highest remaining risks.

On Aug. 11, their streak of good luck ran out.

At 11:59 a.m., Staff Sgt. Daryl Cooper of Olive Branch, Miss., was in his barracks when he heard a distinctive buzzing noise that rapidly got louder. An incoming rocket.

Cooper slipped under his bunk and waited. Then came the sharp crack of the detonation in a riverbed near the camp. A miss.

That was Cooper’s signal. He jumped up and rushed to the command center, where he radioed for an airstrike from the U.S. jets circling the sky above eastern Afghanistan.

Most of the soldiers had run for the bunkers spread around the compound. Nearly everyone sought cover except the artillerymen. They sprinted to their guns, anticipating the computer-quick information from the team that handled targeting.

Some looked up at the mountainsides, where the insurgents very likely were preparing another rocket.

Within minutes, U.S. artillery units usually could locate the enemy position and retaliate with massive counter-fire. There are restrictions on firing into populated areas, but the brush-dappled mountainsides around the base had few buildings or homes. The targets were usually bushes where the enemy was hiding, which made it easier to give the go-ahead to fire quickly.

This time, however, the American guns stayed silent. Five minutes after the first rocket, a second one hissed out of the sky and smacked into a building where several artillerymen were calculating target locations.

It detonated with a muffled thud. The 26-year-old Herrera was killed instantly. Also dead was Spc. Keith E. Grace Jr., 26, of Baytown, Texas.

Grace, who’d been adopted and had overcome cancer as a child, had beaten tougher odds than rockets. But now he was gone.

Several other soldiers were badly wounded, including Orosz, Lambert and Sgt. Jamar A. Hicks, 22, of Little Rock, Ark., the father of a 1-year-old boy.

In an instant, nearly a third of the men in the long-lucky artillery platoon were down.

Civilian contractor Brad Riffel of Engineering Solutions and Products was responsible for surveillance of the terrain around the base found the enemy’s targeting spotter in the mountain range above Wilderness, but it was too late.

As Cooper coordinated the airstrike and Riffel kept searching the mountainsides with his high-tech equipment, 25-year-old Spc. Charles Lane, a combat medic from Christiana, Tenn., frantically went to work in the outpost’s tiny field clinic. He tried to stabilize the wounded men until a medevac chopper could arrive.

The wounded were quickly flown to the field hospital at massive Camp Salerno in neighboring Khost province. The dead followed in another helicopter.

After the choppers left, Lane was visibly exhausted, but calm.

“One soldier had a wound the size of a fist,” he said. “You do everything you can, but sometimes, someone out there on the other side says, ‘He is mine! I’m taking him now!’ ”

Later Lane, still pale, carried the belongings of one of the dead soldiers across the camp in a plastic bag.

At Salerno, Hicks died of his wounds. The others survived.

Four days later, Lambert had recovered enough to log in to his Facebook account, where he changed his cover picture to a somber shot of his three lost friends’ upright boots and rifles from the traditional unit memorial ceremony. He said by email that he expected to recover at Salerno and return to Wilderness.

After Cooper called in the airstrike it took only minutes for the planes to drop several 500-pound bombs on the suspected position of the shooters.

This time, though, there were no confirmed enemy dead. Just this once, the insurgents had won the duel.

That night, in a gesture of solidarity with the Americans, the Afghan artillery battery stationed near Wilderness fired round after round of artillery shells into the abandoned enemy position. The Afghans also sent combat patrols to hunt for additional enemy rocket teams as the Americans grieved.

“Thirty rockets in 30 days,” said Capt. Michael Finch, the commander of Gunfighter Company. “They were bound to hit something. The odds were simply against us.”

His soldiers and the others at Camp Wilderness most likely will be the last Americans stationed there. They’re scheduled to leave at the end of the year.

Until then, their deadly duel, one of America’s last in Afghanistan, is expected to continue.

Click here to read the article in McClatchy.

Click here to read Gady's piece, "Afghan Forces Not Worries about U.S. Departure," in The Diplomat. 

Click here to read Gady's account of talks between high-level Afghan security officials, who recently assumed control over the nation's national security, in World Policy Blog.