Sighting-In a Rifle
Rifle bullets don’t travel in a straight line. They travel in an arc, formed by the pull of gravity. "Sighting-in" is a process of adjusting the sights to hit a target at a specific range. Deer hunters, for example, may sight-in their rifle to hit the bull’s-eye at 100 yards. Depending on the trajectory of the bullet, this gives some variance in the game being closer or farther away than 100 yards so that the bullet still hits the vital organs without compensation or guesswork on bullet rise or drop.
All rifles should be sighted-in before every hunt using the ammunition you plan to use, especially rifles with peep or telescopic sights. Guns you sighted-in prior to your last outing could have been knocked out of alignment by a single jolt. That misalignment could mean the difference between a successful hunt and a disappointing experience.
Many hunters research ballistic charts from ammunition manufacturers and reloading companies to get information on the bullet’s rise and drop at varying distances for the ammunition they use. This allows shooters to sight-in at a specific distance. Then they can adjust their sights for the distance at which they typically shoot their game without shooting a lot of expensive ammunition or they can adjust for other distances if they cannot find firing ranges with the target distances they need.