This article is for most bolt action rifles where you can remove the bolt and look down the bore. Lasers are valuable if you can’t bore sight.
Here is the Sight-in Rule of Thumb for 25 yards for a 1/4″ per click at 100 yard scopes:
4 clicks moves the crosshair 1 inch at 100 yards (indicated on your scope dial or caps)
Most importantly at 25 yards it takes 16 clicks to move the crosshair 1 inch.
Here is a simple method I use when bore sighting a hunting scope that has 1/4 inch per click at 100 yards:
- Bench rest your rifle front and rear with sand bags so it is stable and points to the target without much effort.
- Remove the bolt and look through the rifle bore at a 25 yard target bullseye
- Now without moving the rifle (much) , look through the scope.
- Observe where the crosshairs are when the bore is on target. They could be very far off the bullseye, e.g., high, low, left or right.
- Dial the cross hairs up or down (don’t listen to the clicks, just rotate the dial) without moving the rifle so the bore and crosshairs are on the bullseye.
- Ok, if you believe both crosshairs and bore are close then take a shot at the 25 yard target.
- Now your bullet struck 3 inches low and 2 inches left. Not bad, your on paper! But you want to hit the bullseye! For 25 yards you must rotate your elevation dial 4 times as much or 16 clicks for every inch you are off the target. Thus 3 inches x 16 clicks/inch = 48 clicks. I know… that is a lot of clicks right?
- Now move the windage crosshair 2 inches to the right or 16 clicks/inch x 2 inches=32 clicks.
- Shoot a single round…and believe!
- Move your target to 100 yards and shoot a single round. Your bullet is 2 inches right and 2 inches high. At 100 yards each click is 1/4 inch. Adjust windage left 8 clicks and elevation 8 clicks down. Fire a shot!
- At this time you should be very close to the bullseye and you have only shot 3 rounds. Now with your best sand bag bench rest shoot three shots and see what kind of group sizes you are shooting. Today’s rifle’s often shoot 1 inch groups or better, which is the same as 1 minute of angle (MOA) or better.
- If you are near to 1 or 2 inch groups then find ammo that will shoot to your liking for the game you are after.
Personally I would not hunt deer size game with a bolt action rifle that shot worse than 2 inches from a bench rest at 100 yards, but that is just me. Most new rifles are capable of so much better with the right load… so experiment. I strive for at least 1 inch groups.
Using a ballistic calculator for longer distances helps. I use www.jbmballistics.com
At longer distances, wind become a very large factor.
Good Shooting!
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