Accurately calculating a bullet’s point of impact gets exponentially more complicated as the shot gets longer. And so your odds of hitting go from good to bad to much worse. Once you get to the 400-yard mark, a host of factors come into play that most hunters and shooters rarely think about. Things like swings in air temperature, variability in muzzle velocity, pulling the trigger when your crosshairs aren’t quite level, and how the wind affects the shot. It’s learning to account for these variables that makes long-range shooting rewarding, but they should also serve as cautionary notes for anyone wanting to hunt at extended ranges.
Here’s a breakdown of how these factors influence a fairly standard bullet—a 178-grain boattail fired from a .308 Winchester at 2600 fps—as it travels downrange. These figures are based on a shot taken at sea level in 65-degree weather and 50 percent relative humidity.
With your scope mounted 2 inches above the bore, the bullet will cross the line of sight at about 70 yards before dropping back down to the 100-yard zero.
The bullet will drop 4 inches from the 100-yard zero at this distance, meaning you can hold dead on the 8-inch vitals of a deer with confidence out to this range. Longer shots require adjustments.
If you don’t have a bubble level somewhere on your rifle, you can bet that your crosshairs are tilted when you shoot. Tipping the rifle by just 5 degrees will cause the bullet to impact 2.5 inches off to one side or the other at this range. This effect gets much worse as the distance increases.
In a 10 mph crosswind, the bullet will drift 8 inches here, which can turn a solid hit into a miss, or worse, it can lead to a wounded animal.
A bullet shot into a crosswind will yaw up or down, depending on the direction of the wind and the rifle twist. With a 10 mph wind from the right and a right-hand twist, the shot will strike 2 inches high.
Velocity drops to 1700 fps, at which point many bullets don’t reliably expand enough to ensure quick, clean kills.
Bullets fly with the tip pointed slightly up. This exposes the belly of the bullet to more airflow, causing it to shift sideways. At this distance, spin drift moves the point of impact by 2.5 inches. At 1,000 yards, it will account for an extra 8 inches of windage.
The bullet has been flying through the air for one full second, which is plenty of time for an animal to take a step and for the shot to miss the mark.
Shooting at an angle causes the bullet to impact high, but the adjustment isn’t the same for an uphill shot as it is for a downhill one. Shooting downhill at 15 degrees will cause the bullet to hit 27 inches high. Shooting uphill at the same angle will make the bullet impact 8 inches above the point of aim.
Bullets from the same box of ammo rarely exit the muzzle at the same speed. A drop of 30 fps, which isn’t unusual, will cause the bullet to impact 6 inches low.
A temperature drop of 30 degrees will make the bullet hit a foot lower at this distance.
Underestimating by 10 yards will cause the bullet to hit 10 inches low at this distance.
At 300 yards, tipping the rifle slightly led to a noticeable change in POI. At 1,000 yards, that 5-degree cant is catastrophic, causing the bullet to miss by about 4 feet.
The bullet slows to Mach 1 and experiences turbulence, which can destabilize the projectile, causing it to veer well off course.
To make a shot at 1 mile with this .308, you need to account for the 180 feet of bullet drop it will experience during its four-second journey from the muzzle to the target. At this point, the bullet is traveling only 860 fps, which is about how fast a 230-grain FMJ exits the barrel of a 1911 .45 ACP.
