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.
Your sight should be aligned before each time you go hunting. Aligning your sight will help you gain confidence in the Field, achieve better shot placement, and allow you to practice before heading out into the field.
To help with proper sight alignment it may be useful to purchase some "sight-in targets" that can help you properly adjust your sight. These will also contain instructions on proper sight-in procedure.
First, set up at 25 yards; take aim and fire three shots at the center of the target. These should form a small group of shots on the target, known as a "shot group". If the shot group is not located around the center of the target, you will need to adjust your sight accordingly. Next, move out to 100 yards and repeat these steps.
Your sight's owner's manual will also contain valuable information on proper sighting-in procedure. It is also helpful to get help from an experienced rifle shooter until you're confident in sighting in your rifle.