In November 2009, British sniper Sgt. Craig Harrison recorded the longest confirmed kill ever recorded — 2,705 yards, or a little over 1½ miles. In this excerpt from his new memoir, “The Longest Kill,” Harrison describes the scene: From high ground, he was to protect a patrol of Yorkshire Regiment troops (“Yorks”) and the Afghan National Army in southern Afghanistan. His nemesis: a Taliban “dicker,” or spotter, who was tipping off the enemy.

As I scanned through my binos, I could see the Yorks’ patrol base. I could also see the large three-peaked hill, almost two miles away, that they would be patrolling toward.

“Three Titted Hill,” as it was known in the Army, was covered in compounds and Taliban rat runs. They could sneak through this area with impunity and hit the patrol bases whenever they wanted. The Yorks and the ANA were going to try to clear this area.

A glint off in the distance caught my eye. The old “sniper sense” started to kick in.

My spotter Cliff and I trotted about 20 yards to our front and crouched behind an old wall. It was neck height; perfect for me to balance the rifle on. The downside was that the mud wall was in pretty bad shape and starting to crumble.

I put my rifle by my feet and pulled out my map, working out a hasty range card. Then I rummaged in the top of my daysack and pulled out my wind markers: tent pegs with para cord hanging off them. I put two out, one on either side of me.

I needed to find the dicker. He was the Taliban’s eyes and ears, and without him they were headless. It was almost 1030 hours now and the sun was shining. There was a glint off in the distance, from the spot where I’d seen movement before.

It was a long way off, almost at the base of Three Titted Hill.

Movement caught my eye again in the same place, just to the left of a compound. I focused my scope in and scanned the area. Another glint. Finally, I could see a bearded, turbaned man. The glint was coming from the antenna of the radio he was holding.

“Cliff, got him.”

Off the scope

I reached over and began dialing clicks into the elevation drum of my scope. I had the best sniper rifle in the world, an Accuracy International AWM .338, and the best telescopic sights, the Schmidt & Bender 5-25.

When you fire a shot through a rifle, the bullet flies on a parabolic curve; it doesn’t fly straight. It gains height before dropping because of gravity. The sniper needs to know the range so that he can dial corrections into the scope to compensate for the bullet’s flight path.

I dialed a massive correction into my scope. I was going to have a go. I’d never shot this far out, and, from everything I had been taught, the .338 round wouldn’t go that far. You never knew, though, and if I could get a round in the general area, it might keep the dicker’s head down.

There is so much to take into account with extreme long-range shooting: range, temperature, humidity, wind speed and direction, even flight time.

Four pounds of pull is all that it takes to cause the trigger to “break.” Once the hammer falls, the .6-ounce bullet will leave the barrel at a speed of around 3,000 feet per second.

A bullet takes around two seconds to reach 1,000 yards. That meant that, at this range, my round would be in flight for 5 to 6 seconds. During that period, the Earth would have actually moved, what’s known as the Coriolis effect.

I went through my preshot routine. I cleared my mind, regulated my breathing and concentrated on keeping the rifle as level and as stable as possible. I took up the slack on the trigger and exhaled. I had the Taliban; at this range he was a very small object in the scope, right in the center of my cross hairs.

At the peak of my exhale, I pulled the trigger and the rifle barked into my shoulder. I quickly recovered from the recoil and the scope settled. I waited six seconds and didn’t see anything, except a very much alive Taliban. I had no idea where the shot had gone.

My round would be in flight for 5 to 6 seconds. During that period, the Earth would have actually moved, what’s known as the Coriolis effect.

“Miss,” said Cliff.

“I can f – – king see that; where did it go?”

“Low, very low, about 150 yards below him.”

I quickly dialed more adjustments into the scope and fired again.

“Low,” he said.

We repeated the process eight times, the dicker oblivious to the fact that someone was targeting him and that he wasn’t just hearing stray shots on the battlefield. Each time Cliff spotted the impact and I made an adjustment to my scope.

By the ninth shot, I had run out of clicks in the scope and was at the bottom part of the central pillar of my cross hairs.

I was literally out of scope. The ninth round struck the wall just below the dicker, though, sending him sprawling for cover. Finally, I was now in the field of vision for my scope — so I could see where my bullets were hitting and more precisely calculate the adjustments I needed to make.

I made my own minor corrections and as soon as I saw the dicker’s head I fired again.

Miss.

I fired another four rounds, none of which gave me the spray of red mist I was desperate to see, but at least I was keeping his head down.

Ambush in the mud

Out of the corner of my eye, I saw two Jackals start to drive down the center of the valley. Straight into the potential kill zone of the Taliban ambush.

I quickly got on my radio to higher headquarters.

“Zero Alpha, this is Maverick 41. Why are you driving into terrain that is a potential ambush site? Over.”

“Roger, this is the only available route in and out and we need to keep it open for the patrol. Out,” was his response.

Now I had to try to keep the dicker’s head down, provide overwatch for the patrol and provide cover for the vehicles.

Then it all kicked off. The Yorks patrol got attacked on multiple flanks. I would have to deal with the dicker later; this was a more pressing threat.

More and more Taliban were swarming into the area and the sound of gunfire and explosions in the valley was increasing by the second. It looked like the Yorks, the ANA and the remainder of my troop were getting further and further into the s – – t. I had to help in any way I could and right now that meant neutralizing as many insurgents as possible.

All of the vehicles suddenly stopped and I could see one of the lads, Mark, dismount and start to walk round his vehicle. I knew I wouldn’t stop in the middle of a kill zone.

“Wit, talk to me. What is going on?” I called to one of the men with me.

“One of the Jackals is bogged in,” he replied. “It looks like the Taliban have been flooding the fields to trap the vehicles.”

“Tell them to hold on while I scan the area.”

I’d just started to search around the vehicles when a large weight of fire started up. All of the lads hit the deck.

“Contact, contact,” Wit shouted, relaying what he had just heard on the radio.

Dust was kicked up all around them and I could see Mark trying to get back into his vehicle to get the machine gun to bear, but the fire was just too heavy around him and he was forced to jump into a nearby ditch.

“Cliff, help me check all of the firing points. We’ve got to help the guys,” I said.

We both started searching all of the previous places we had seen Taliban but they were clear.

I needed to stay calm. I could feel my heart rate rising and my muscles tensing. I was desperate to help my lads, but would be no use if I couldn’t shoot properly. I took a deep breath and forced myself to relax.

“Where the f – – k is that machine gun?” I muttered.

It suddenly occurred to me that the only place we hadn’t checked was around the dicker.

Taking the shot

The machine gun with the longest range that the Taliban had was a PKM, a belt-fed machine gun capable of shooting out to 1,600 yards. That meant that they had to be . . . on Three Titted Hill.

I brought my rifle round, scanned the area of the far compound where the dicker had been and suddenly I saw them.

A Taliban machine-gun team was up on the right-hand side of the compound, pouring fire down on my lads. Whereas I had been happy just to keep the dicker’s head down, I knew I had to get these guys — or they were going to kill one of mine. This time the rounds had to count.

I glanced at my wind markers. They were hanging limply; good, no wind. I was already at maximum elevation on the scope but I dialed 20 clicks left to take account of the spin drift, then factored in the Earth’s rotation.

I lifted my head up an inch and then placed it back down, checking my eye relief (how far back my eye was from my scope). I ensured I had a good cheek weld to the stock. The sponge that I’d put on the stock the other day was doing its job, even though it was soaking wet with sweat.

My left hand was getting sore from holding on to the scope for so long, but I just had to push through it.

The rifle was comfortable in my shoulder and I could feel that I was getting into the most stable position that I possibly could. I still wasn’t happy, though. I was standing on a small incline, which meant my right knee was slightly bent. By now it was trembling with strain.

“Cliff, grab a rock and shove it under my right heel. I need to get my foot as flat as possible.”

Cliff scuttled over and shoved a rock under my foot so that I was nice and even. All of this activity took mere seconds.

Finally, I was ready. I placed my aiming mark on the machine gunner, took up the trigger slack and started to exhale.

I paused on the trigger’s break point and a sense of calm washed over me. I continued the squeeze and fired.

Then, all I could do was watch intently through the scope for six long seconds. Miss.

“S – – t, f – – k,” went through my head.

I cycled the bolt again. The machine-gun crew were looking around. They knew that a round had just passed very close to them.

I fired again.

Six seconds later, I watched the machine gunner slump down on the PKM. Hit. Hit.

I couldn’t believe it and had to fight an almost uncontrollable euphoria.

“Keep calm,” I thought to myself. “Take out the other one.”

I quickly got another round into the chamber and fired at the machine gunner’s number two. Miss.

The second gunman picked up the PKM and started to turn. I cycled the bolt, setting myself up for the next shot.

“He’s moving,” shouted Cliff.

It was now or never. I knew what I needed to do, I knew where I needed to aim, I knew everything that I needed to take into account. In the blink of an eye, I fired.

And six long seconds later, I watched as the second gunman collapsed.

Going the distance

Once I was happy that there were no other threats out there, a sense of relief washed over me. My mates were out of danger.

An hour later, the remainder of the troop pulled up onto our little piece of high ground. The lads were all pumped with adrenaline and started thanking me.

“Did you really get those guys from here?” Andy, the troop leader, asked, with disbelief in his voice. He thought that I’d just scared them away. I gave him my rifle and he looked through the scope. The two bodies were still there.

“F – – k me,” he said, in his posh Cavalry officer tone.

I just grinned.

Excerpted from “The Longest Kill: The Story of Maverick 41, One of the World’s Greatest Snipers” by Craig Harrison. Copyright © 2016 by the author and reprinted by permission of St. Martin’s Press, LLC.