As everyone who wasn’t passing notes in science class knows, a bullet fired from your pistol and a bullet dropped from the same height will hit the ground at the same time.
(If you were passing notes in science class, this was proved by dead Italian guys a long time ago using cannons and tall buildings and the kind of experiments that will get a SWAT team called on you if you try and repeat them today.)
Once the projectile leaves the muzzle, gravity grabs hold of it and it starts falling. This is offset by angling the sights so that the barrel is pointed slightly upward. Since the bullet travels in a curved path and the sighting plane is a straight line, the two will only cross exactly in one place. Well, two, but with handguns we’re only really concerned with the first one.
This is the source of some people’s confusion with laser sights. In Hollywood, lasers work like some magical bullet-guidance system; wherever the dot is placed, that’s where the bullet lands. In reality, as we saw above, the bullet travels a curved path while the laser beam travels a path that is, er, laser-beam straight, and we’re back to the two only precisely intersecting at one specific distance. At all other ranges, the laser is only a rough indicator that the projectile will impact somewhere nearby.
When fired from the same pistol, heavier bullets hit higher than lighter ones.
Back to trajectories. Unlike long-distance rifle shooting, bullet drop is rarely a significant factor in handgun shooting. At twenty-five yards, even the comparatively slow-moving 230gr. .45 ACP bullet has had just enough time to fall barely two inches. It’s only when you get out to fifty yards and beyond that noticeable differences in pistol bullet trajectories start to appear.
However, there’s another component to sighting in a pistol that is different to sighting in a rifle. Since, by and large, pistols are much lighter than rifles and their bullets move much more slowly, the gun jumps around a lot more while the bullet is still in the barrel. This leads to a seemingly paradoxical effect: When fired from the same pistol, heavier bullets hit higher than lighter ones.
You see, the heavier bullet recoils more, causing the muzzle to lift to a greater degree before the bullet exits. If you increase the powder charge on the lighter bullet to make it have as much recoil as the heavier one, then the lighter bullet is sped up and leaves the barrel sooner, and it will still impact lower.
It’s important, therefore, to know where the pistol will hit for you. If your friend Joe, who has a grip like a bench vise and shoots 115gr. bullets sells you his laser-sighted pistol, don’t be surprised if, in your lighter grip, your 147gr. projectiles impact significantly higher than the red dot. Don’t blame Joe; it’s all the fault of those dead guys and their physics. Sight the gun in yourself, and sight it in using the same ammunition you intend to use if you have to use it for real.
[ Tamara Keel has been shooting guns as a hobby since she was eighteen. She has worked in the firearms business since the early 1990s. Her pastimes include collecting old guns, writing, and being bossed around by house cats. ]