to the target. That powder has to explode fast, explode completely, and explode hard. Difficult chemistry. Weight for weight, that explosion has got to be the best explosion on the planet.
Then mechanical engineering takes over for a spell. The bullet itself has to be a perfect little artifact. It's got to be as good as any manufactured article has ever been. It has got to be cast better than any jewelry. It must be totally uniform in size and weight. Perfectly round, perfectly streamlined. It has to accept ferocious rotation from the rifling grooves inside the barrel. It has to spin and hiss through the air with absolutely no wobble, no bias.
The barrel has to be tight and straight. No good at all if a previous shot has heated and altered the barrel shape. The barrel has to be a mass of perfect metal, heavy enough to remain inert. Heavy enough to kill the tiny vibrations of the bolt and the trigger and the firing pin. That's why the Barrett Reacher was holding cost as much as a cheap sedan. That's why Reacher's left hand was loosely clamped over the top of the gun. He was damping any residual shock with it.
Optics play a big part. Reacher's right eye was an inch behind a Leupold amp; Stevens scope. A fine instrument. The target was showing small, behind the fine data lines etched into the glass. Reacher stared hard at it. Then he eased the stock down and saw the target disappear and the sky swim into view. He breathed out again and stared at the air.
Because geophysics are crucial. Light travels in a straight line. But it's the only thing that does. Bullets don't. Bullets are physical things which obey the laws of nature, like any other physical things. They follow the curvature of the earth. Eight hundred and thirty yards is a significant piece of curvature. The bullet comes out of the barrel and rises above the line of sight, then it passes through it, then it falls below it. In a perfect curve, like the earth.
Except it's not a perfect curve, because the very first millisecond the bullet is gone, gravity is plucking at it like a small insistent hand. The bullet can't ignore it. It's a two-ounce copper-jacketed lead projectile traveling at nearly nineteen hundred miles an hour, but gravity has its way. Not very successfully, at first, but its best ally soon chips in. Friction. From the very first millisecond of its travel, air friction is slowing the bullet down and handing gravity a larger and larger say in its destiny. Friction and gravity work together to haul that bullet down.
So you aim way high. You aim maybe ten feet directly above the target and eight hundred and thirty yards later the curvature of the earth and the pull of its gravity bring that bullet home to where you want it.
Except you don't aim directly above the target. Because that would be to ignore meteorology. Bullets travel through air, and air moves. It's a rare day when the air is still. The air moves one way or another. Left or right, up or down, or any combination. Reacher was watching the leaves on the trees, and he could see a slow steady breeze coming out of the north. Dry air, moving slowly right to left across his line of sight. So he was aiming about eight feet to the right and ten feet above where he wanted to put the bullet. He was going to launch that projectile and let nature curve it left and down.
Human biology was all that stood in the way. Snipers are people. People are quivering, shuddering masses of flesh and muscle. The heart is beating away like a giant pump, and the lungs are squeezing huge volumes of air in and out. Every nerve and every muscle is trembling with microscopic energy. Nobody is ever still. Even the calmest person is vibrating like crazy. Say there's a yard between the rifle's firing pin and the muzzle. If the muzzle moves a tiny fraction, then eight hundred and thirty yards later, the bullet is going to miss by eight hundred and thirty tiny fractions. A multiplying effect. If the shooter's vibration disturbs the muzzle by even a hundredth of an inch, the bullet will be eight-point-three inches off target. About the width of a man's head.
So Reacher's technique was to wait. Just to gaze through the sight until his breathing was regular