Although gravity and wind are the main influences on a bullet’s path, there are certainly some other factors to consider as well. One of these is the initial bullet speed.
How does initial bullet speed play into external ballistics?
- Bullet speed does not lessen or increase gravity’s effects.
- It merely gives more or less time for the force to act on the projectile.
- Three things determine speed: a bullet’s initial speed, its efficiency and environmental variables.
- A longer barrel permits a faster bullet, but this doesn’t equate to more accuracy.
- Temperature also can affect velocity.
Hopefully, we dispelled the myth that a fast bullet somehow resists gravity. Instead, a fast bullet merely gets to the target faster and therefore has less time to fall. Also, the longer it takes for a bullet to reach a target, the more exponentially it falls.
In an example we used, a bullet from my .308 Winchester only falls 4 inches between the 100- and 200-yard berms, but it falls almost 100 inches between the 900- and 1,000-yard berms. The bullet falls more when it’s farther away because it is traveling slower (it takes longer to cover the 100 yards between berms), and it is also falling faster.
When we discuss wind in a future article, you’ll see that the amount of time a bullet is exposed to wind (how long it takes to get to the target) also has a direct effect on how much a bullet is blown off of its original path.
Gravity And Wind
At a basic level, the two main things that will affect your bullet’s path are gravity and wind. All of the other variables you hear about — air pressure, temperature, altitude and humidity — don’t affect the bullet’s path. Instead, those variables only change how much gravity and wind can affect the bullet.
Of course, there are other things that will affect your bullet’s path. For example, the spin of the earth and the spin of your bullet can both change a bullet’s path. However, let’s save those for a future discussion once you understand the basics first.
There are three variables that determine a bullet’s speed on its way to the target:
- The initial bullet speed
- The efficiency of the bullet
- External/environmental variables
In this piece, we’ll explore initial velocity. The other variables will be discussed in future columns.
Don’t fall into the trap of thinking that faster is always better. There are many shooters who chase the newest fad cartridge to get whatever velocity increase they can. Yes, a faster bullet has less time to fall and be affected by the wind, but just because it is faster doesn’t mean it’s necessarily better overall.