Simplified, the firing process works this way: 1. A striker, or
firing pin, hits the primer which, in turn, burns the powder. 3.
Gases inside the chamber expand and propel the bullet forward 5.
If the barrel has rifling, 6. the groves force a spin in the
bullet. 7. Immediately after the bullet leaves the muzzle, air
friction decelerates it 8. and gravity pulls it down Rifling and
Bond, James Bond Bullet trajectories are parabolic, in theory at
least. Although friction caused by air molecules decelerates
projectiles, trajectories are close to a parable. Therefore,
they should travel a predictable path. However, wind, barrel and
bullet shape imperfections and other factors contribute to a
less than perfect shot. Add to those, the human factor: When the
hunter shoots, the weapon recoils and he wobbles a bit. This
wobble, although imperceptible, is strong enough to affect the
bullet. In short, the trajectory of a bullet is anything but a
straight line. To help stabilize the trajectory, barrels have 2
to 8 spirali