Simple 4-Shot Sight-In Method
Here’s a simple procedure that lets you get a solid zero for a hunting rifle in just four shots. Of course you probably want to fire a few more rounds to confirm your zero before you head off to your hunting grounds, but this will let you get on-target with a minimum amount of time and ammo expended. (This assumes your scope is securely mounted, and the bases are not drastically out of alignment.)
1. First, remove the bolt and boresight the rifle. Adjust the position of the rifle so that, looking through the bore, you can see the center of the target with your eyes. Secure the rifle in the rests to maintain its position as boresighted. Then, without moving the rifle, center the reticle. That should get you on paper. With the rifle solidly secured in front and rear rests or sandbags, aim at the center of a target placed at your zeroing distance (50 or 100 yards). Confirm there are no obstructions in the barrel! Then load and fire one shot. Then, return the gun to the exact position it was when you pulled the trigger, with the cross-hair centered on the target as before.
2. Locate, in the scope, where your first bullet landed on the target. Now, while you grip the rifle firmly so it doesn’t move, have a friend adjust the turrets on your scope. While you look through the scope, have your friend turn the windage and elevation turrets until the cross-hairs, as viewed through the scope, bisect the first bullet hole on the target. In other words, you use the turrets to move the center of the reticle to the actual position of shot number one. Dial the crosshairs to the hole — don’t move the rifle.
3. After you’ve adjusted the turrets, now re-aim the rifle so the cross-hairs are, once again, positioned on the target center. Keep the rifle firmly supported by your rest or sandbag. Take the second shot. You should find that the bullet now strikes in the center of the target.
4. Take a third shot with the cross-hairs aligned in the center of the target to confirm your zero. Make minor modifications to the windage and elevation as necessary.
5. Now shoot the rifle from a field rest (shooting sticks, bipod, or rucksack) as you would use when actually hunting. Confirm that your zero is unchanged. You may need to make slight adjustments. Some rifles, particularly those with flexy fore-arms, exhibit a different POI (point of impact) when fired from a bipod or ruck vs. a sandbag rest.
If you recently cleaned your rifle, you may want to fire two or three fouling shots before you start this procedure. But keep in mind that you want to duplicate the typical cold bore conditions that you’ll experience during the hunt. If you set your zero after three fouling shots, then make sure the bore is in a similar condition when you actually go out hunting.