"Never let your gun suffer from separation anxiety, Always carry." ~ The Recoil Recitals

Saturday, June 25, 2016

Sighting in a new scope is such a pain... Or is it?

Zeroing your new scope seems to be one of the biggest mysteries out there.  I am going to take you through how to properly zero your scope and hopefully clear up misconceptions you may have about the topic. I will be using a 2.125” sight height, 1/8" @ 100 yds. or 1/8 MOA (Minute of Angle) per click and Freedom Munitions Remanufactured FMJ .308 Win 150 gr. cartridge for reference. I normally zero in at 50 yards, as this is an easily obtainable distance. The Freedom Munitions Remanufactured FMJ .308 Win 150 gr. has a muzzle velocity of 2,810 f.p.s. and a ballistics coefficient of .398. A 50 yd. zero will put you approximately -1.49 MOA @ 200 yds. So there will not be much adjusting needed to be made inside those distances. Beyond those distances, simple elevation corrections are dialed in via the elevation turret on the scope -7.13 MOA @ 400 yds. -10.69 MOA @ 500 yds. for reference.

Let’s Boresight the Scope.

1) Mount the scope to the rifle using the rings. It’s easy to mount your scope slightly crooked. Over torquing when screwing the top ring down can slightly cant the scope, and that slight cant is all takes to throw it off. Using a scope leveling kit can help drastically.

2) Center your scope’s turrets (windage and elevation knobs). This is done by turning the turret all the way in one direction left or right. Start with the elevation turret and turn it all the way up, then turn it all the way back down, while counting the number of clicks it takes until it stops. Divide that number by 2, and then turn the turret that many clicks the other way. This will center the crosshairs, now do the windage turret. Your crosshairs are now centered, not zeroed, centered. *This is an optional step, you can just start from where they are.

3) With the scope now mounted, crosshairs centered (if you chose to do so) and the rifle is unloaded. Take the gun to a place where you can see about 50 yds. away. This can be done outside or it can be done inside while looking through a window. Remove the bolt from the gun, so that you can see through the barrel.

4) Secure the gun with shooting bags, a gun vise, or the gun’s bipod whatever you have and point it at an object 50 yds. Away.  Look inside the barrel of the gun, and center the barrel of the gun on a distant object.

5) Without touching the gun, lift your eye up to the scope. Do you see the same object? If so, is the scope centered on the same object that the barrel is? If it does that’s great. Chances are it will not work out like that.  If it doesn’t; which it probably won’t, slowly turn the elevation and windage knobs until the center of the crosshairs matches the view inside the barrel.
Once your crosshairs point to what you see through the barrel; you are “bore sighted” and you should at least be on paper with your first shots.

Time to throw some lead!

6) Securely support your rifle using sandbags, a gun vise or a bipod. The less you touch the rifle the better.  Load 1 round into your rifle. Line your crosshairs on the center of your 50 yd. target, squeeze off a shot; remembering to use proper technique including breath control, trigger squeeze, cheek weld and sight picture.
Where did you hit, High, Low, Left, Right?  If you can’t see the shot through the scope, walk downrange to the target and look, if allowed. A spotting scope or binoculars are very useful in this situation.

7) After verifying shot placement, look through the scope and align the crosshairs on the center of the target. Ensuring to keep the rifle steady, turn the windage and elevation knobs until the crosshairs are centered on the hole of your shot.

8) Fire another round, aiming for the center of the target. Your shot should be dead on. If not, repeat steps 6 and 7. Once your scope is zeroed, it is a good idea to remove the windage and elevation turret caps, using your manufacturer's instructions; without allowing the turrets to move any clicks, take the turret caps off and place them on the zero marks aka slip the scales.

9) Once you have slipped the scale you should find you mechanical zero (true zero of your scope now). This done by turning you elevation turret all the way up; you do noy need to count clicks you can count full rotations. Write the number down. Return your scope back to zero by turning the turret back the other way the same number of rotation to the zero mark.

You are now zeroed for 50 yds. You should fire at least 3-5 more shots just to verify your zero.

Will my Scope Stay Zeroed?

Your scope should remain zeroed unless you drop it, bump it hard against something or any of the following statements are true.
I used a sufficiently different load of ammunition than the one I zeroed with.
I used a heavier or lighter bullet than the bullet than the one I zeroed with.
I did not use proper technique including, holding my rifle differently, I had a different cheek weld, my breathing was erratic, I did not squeeze the trigger I pulled it.

"Never let your gun suffer from separation anxiety, Always carry."

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