Sight Alignment of a Rifle
The flight of a bullet is not a straight line to the target. Gravity, air resistance and energy loss all have an effect on flight. A hunter must always take that into consideration when sighting-in. A bullet sighted-in to hit a bull's eye at 100 yards might be one inch above the bull's eye at 50 yards. The hunter needs to know what type of game will be hunted and only sight-in with the ammunition that will be used in the hunt.
The key to sighting in a firearm is to reduce all movement of the shooter and the rifle. The hunter needs a good solid bench to sit at, and a solid rest for the firearm - sandbags, carpeted wooden blocks or a tripod all work well. It is important that a hunter exercise breath control at the moment when the trigger is pulled because the rise and fall of a hunter's chest when breathing can influence a bullet's trajectory.