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Thread: Methods of zeroing a scope

  1. #1

    Default Methods of zeroing a scope

    I will soon be mounting and zeroing a new scope on my .338 Mag. and was interested in how you guys zero your scopes and rifles. In the past I have always bore sighted and then made sure I was on target at 25 yards and then moved out to 50 yards and then finished at 2" high at 100 yards.
    I always have made adjustments to my scopes by calculating the proper number of clicks for the range (i.e. at 100 yards a scope with 1/4 m.o.a. adjustments should move the shot group a 1/4" per click). This has worked okay, but I have only had one scope that actually moved the shot group the amount it was suppose to. With the others, I would have to mess with them until I finallly ended up where I wanted, which of course was irritating and a waste of ammo. Is this rare, do others find their scope adjustments to be accurate and consist?
    Also, I was interested in finding out how many of you guys zero your rifles by firing a shot at the bullseye, then lining up the crosshairs on the bullseye, and adjusting your scopes cross hairs to your last shot taken (the prior bullet hole)? I have never tried this method, but it seems like an easier one. Is their any downside to this method over the previous one mentioned? Thanks for the help and advice.

  2. #2
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    For 30 years, I have zeroed my scopes before firing a shot.

    With the scope mounted correctly and properly torqued in place:

    1. Place a 25 yard pistol or similar bullseye target down range at 100 yards.

    2. Place rifle on a sand bag or similar rest pointed down range.

    3. Remove the bolt from the rifle.

    4. Remove the caps from the scope adjustment turrets.

    5. Look through the bore and move the rifle to center bullseye target in the bore.

    6. Hold the riflein place with the target centered.

    7. Hold the rifle. Looking through the scope, adjust the elevation (horizontal) cross wire of the scope until it intersects the target center. Recheck the rifle bore to target center. Recheck elevation cross wire to target center.

    Note: If the horizontal wire is above target center adjust the turret (U) up.

    8. Hold the rifle, recheck the bore to target center, looking through the scope, adjust the windage (vertical) cross wire to target center. Recheck the bore to target center. Recheck the vertical wire to target center.

    Note: If the vertical wire is to the left of target center, adjust it (L) left.

    Repeat steps 7 & 8 and readjust if necessary.

    9. Replace bolt in rifle and fire one 3 shot group at 100 yards with firm rest and steady hold.

    10. Check target and readjust scope further if necessary. Replace turret covers.

    If this doesn't work, your rifle or scope or mounts need work.

    Generally all scope adjustments are out of spec in regards to the 1/4" or 1/2" per click. With this technique you don't count clicks and don't care.

    Also many scopes need to shoot in. Some shooting will settle the scope to a point that will be stable.

    Only move a scope one axis at a time when adjusting the final POI. Adjust elevation then shoot it and verify elevation, then adjust windage, shoot and readjust. Then shoot the final group. This should leave a good stable setting.
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    Member stevelyn's Avatar
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    Default

    I've found that they already come mechanically zeroed. I just mount them and walk in the rounds one shot at a time, if they're hitting paper, then finish with a 3 round group to confirm.
    Now what ?

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    Member Daveintheburbs's Avatar
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    I usually use Murphys method to boresight, but shoot first group at 25 yards and then proceed as ak hunter mentioned. Last fall after the standard manual bore sight, I tried the "shoot one group (25yards)then after centering the rifle on the target adjust the cross hair to the group" method. Worked like a champ and speeded the process. Usually finish up ~2" high at 100.

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    Default Use a Laser...

    if your using a semi auto...or the Leupold zeroing thingy...

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    Member marshall's Avatar
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    I've been loading for quite a few friends lately.

    When I hit the range with their rifle which I've never shot, I usually fire one round at 25 yards to get an idea of the 100 yard impact point. I adjust that impact point for a bulls eye at 25 yards then move the target out to 100 yards and fire three rounds. I move the center of that group to 2.5" high at 100 and start my re-load data collection.

    Another method that works well at 100 yards is to have the rifle in a secure rest and fire one shot at the bullseye. Re-aim your cross hairs at the bullseye then adjust your windage and elevation knobs to the impact point. The scope should be zeroed after that.

  7. #7

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    Murphy's zeroing process is basically what I do and I've always found it to work very well, I can usually eyeball the POA within a few iches of the POI @ 100 yds.

    On the repeatability of your turrets, most of the non tactical scopes will not repeat reliably, but if they are a good quality scope, they should be fairly close. You can get good repeatable turrets, but they aren't necessary if your not dialing your windage and elevation corrections.

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    Default Quick question...

    If you hitting low on your POI, you want to move the elevation UP correct? Likewise, if your hitting to the left, you want to move the windage to the left as well, correct?

    & At 25 yards, you should only need to move your indicator 1/4 of the way marked on the scope (usually 1/4" moa click at 100 yds. so then a 2" low 2" left shot group should only be moved X amont at 25 yards)

  9. #9
    Supporting Member AFHunter's Avatar
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    Default American or European scope

    [QUOTE=gogoalie;461206]If you hitting low on your POI, you want to move the elevation UP correct? Likewise, if your hitting to the left, you want to move the windage to the left as well, correct?


    Most American scopes are adjusted as in your quote. If you shoot European scopes the oppisite is correct.

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    Member marshall's Avatar
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    Quote Originally Posted by gogoalie View Post
    At 25 yards, you should only need to move your indicator 1/4 of the way marked on the scope (usually 1/4" moa click at 100 yds. so then a 2" low 2" left shot group should only be moved X amont at 25 yards)
    If you have a 1/4 MOA scope adjustment you will need to move it 4 clicks for a 1/4 inch at 25 yards. 1 click is a 1/4 inch at 100 yards and 1 click is 1 inch at 400 yards.

  11. #11

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    [QUOTE]
    Quote Originally Posted by gogoalie View Post
    If you hitting low on your POI, you want to move the elevation UP correct? Likewise, if your hitting to the left, you want to move the windage to the left as well, correct?
    Right on the up, wrong on the left.

    If you're hitting low and you want to move your POI up then click in the "UP" direction as marked on your turret.

    If you're hitting left and you want to move your POI to the right, the click in the "R" (right) direction as marked on your turret.

    The dierection arrows on your turret are the direction the POI is moved.

  12. #12

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    Yes, I do it like Murphy does it. Sure saves a lot of ammo.
    A GUN WRITER NEEDS:
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    Quote Originally Posted by gogoalie View Post
    If you hitting low on your POI, you want to move the elevation UP correct? Yes Likewise, if your hitting to the left, you want to move the windage to the left as well, correct? No, right.

    & At 25 yards, you should only need to move your indicator 1/4 of the way marked on the scope (usually 1/4" moa click at 100 yds. so then a 2" low 2" left shot group should only be moved X amont at 25 yards)
    Actually if one click moves the POI 1/4" inch at 100 yards it moves it 1/16" at 25 yards. So if you want to move the POI 1/4" at 25 yards you would need four clicks.

    For 2" error at 25 yards (this is the same as 8" error at 100 yards) you would move 32 clicks at 25 yards (for a 1/4" per click scope)

    Think of this as a cone of movement that starts at the scope at zero and goes to 1" wide at 100 yards, half way out is 1/2" (50 yards) and one quarter out (25 yards) is 1/4" wide. Four clicks is one inch at 100 yards, 1/4" at 25 yards.


    Is everyone confused now?

    Marshall and Montana both get little gold stars on their book reports.
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



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    Thumbs up Ok...

    Thanks Murphy, I was only doubling my 25 yard adjustments the other day & not quadrupling them...like I should have been...It's clear...

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    Sponsor ADfields's Avatar
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    Question INCH or MOA?

    Quote Originally Posted by Murphy View Post
    (for a 1/4" per click scope)
    That was a very good explaining, even I understood it.

    I think many get 1-INCH and 1-MOA mixed up, they are the same at 100 yards but no other place along the cone. You say 1/4" per click scope but to my knowledge there is no such animal, so you mean 1/4 MOA per click correct?

    I was taught that MOA and degree are one and the same but never believed that 100% since they have different names I suspect there is some reason for it, like bullets travel in arcs maybe. They are never the less very close as there are 360 degrees or 360 MOAs in a complete circle. The size of the circle does not change the number of degrees or MOAs because they measure the angles not the size, inches do change since they do measure size.

    So at 100 yards 1MOA is 1 inch, at 200 yards 1MOA is 2 inches, 300 yards 1MOA is 3 inches and so on to give us that ever expanding cone. At 2MOA we get twice the inches. 100y 2MOA is 2” at 200y we get 4” and 300y is 6” and so on.

    I think we get it stuck in our heads that 1MOA is 1Inch at 100 yards and promptly forget that it’s not at 50 yards or 150 yards. So now we are thinking in inches and not angles that the scopes are built for.

    Now, I hope I helped more people than I confused with my poor explaining of MOA.

    Andy

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    Member marshall's Avatar
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    Quote Originally Posted by Murphy View Post
    Marshall and Montana both get little gold stars on their book reports.
    Thanks professor.

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    Quote Originally Posted by ADfields View Post
    That was a very good explaining, even I understood it.

    I think many get 1-INCH and 1-MOA mixed up, they are the same at 100 yards but no other place along the cone. You say 1/4" per click scope but to my knowledge there is no such animal, so you mean 1/4 MOA per click correct?

    I was taught that MOA and degree are one and the same but never believed that 100% since they have different names I suspect there is some reason for it, like bullets travel in arcs maybe. They are never the less very close as there are 360 degrees or 360 MOAs in a complete circle. The size of the circle does not change the number of degrees or MOAs because they measure the angles not the size, inches do change since they do measure size.

    So at 100 yards 1MOA is 1 inch, at 200 yards 1MOA is 2 inches, 300 yards 1MOA is 3 inches and so on to give us that ever expanding cone. At 2MOA we get twice the inches. 100y 2MOA is 2” at 200y we get 4” and 300y is 6” and so on.

    I think we get it stuck in our heads that 1MOA is 1Inch at 100 yards and promptly forget that it’s not at 50 yards or 150 yards. So now we are thinking in inches and not angles that the scopes are built for.

    Now, I hope I helped more people than I confused with my poor explaining of MOA.

    Andy

    Actually a lot of scopes are marked 1/4" vs MOA but it is close and they probably mean MOA but put 1/4" because most know inches not moa's. This minute of angle of my cone would be determined by the side/angle/side trig function and would come out to be about 1.05" at 100 yards.

    100 yards is 3600 inches, this is the Adjacent side of the triangle, the angle is .016666 degrees (1/60 of a degree), the angular deflection (the scope adjustment) will be the Opposite side of the triangle. T (tangent of the angle) = O/A so we'll transpose that to O=A*T. The T of .016666667 degrees is .000290888 * 3600 = 1.047197581" this is the Opposite side of the triangle. weren't that fun.
    Last edited by Murphy; 03-26-2009 at 10:30.
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



  18. #18

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    Murphy,

    Regarding your comment: "Only move a scope one axis at a time when adjusting the final POI. Adjust elevation then shoot it and verify elevation, then adjust windage, shoot and readjust. Then shoot the final group. This should leave a good stable setting."

    So if I had already shot at 25 yards and had now moved out to 100 yards, and shot a group that was high and right, I would aim at the bull eye again, and move the horizontal crosshair up, to the center of my last group. I would then shoot a new group and hopefully it was now online with the bull eye elevation wise but still to the right. Then I would aim at the bulls eye again and move my windage crosshair to the right untill it was centered on my most recent group. Then shoot again and I should be in the bulls eye. Do I have this correct? Would it be a problem to make both elevation and windage adjustments at the same time and save some ammo while sitting in (does this really affect the stability)? Also, I have heard people recommend tapping the tops of the turrets every time after making adjustments. What are your thoughts on this practice? Thanks for the help.

  19. #19

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    [quote]
    Quote Originally Posted by ak hunter View Post
    Murphy,

    Regarding your comment: "Only move a scope one axis at a time when adjusting the final POI. Adjust elevation then shoot it and verify elevation, then adjust windage, shoot and readjust. Then shoot the final group. This should leave a good stable setting."
    I am not going to argue Murphy's technique of one axis at a time as it is certainly reasonble, but being the impatient guy that I am, I adjust both at the same time. This seemed to work OK with my older Weaver and B&L scopes and with the Nightforce I have now, it is absolutly precise. It moves *exactley* 1/4 MOA per click with each turret, no tapping. As for tapping, of you think about it, it's pretty scarry to think you can "settle" your reticle by tapping on your scope. One would think that those hairs should not move at all except by click adjustments. But hey, that is what I used to do with my B&L. Not sure if that is me making myself feel good or actually settling in the reticles.

    Now I am waiting to see if Murphy will be taking away my gold stars

  20. #20
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    I make bold sight/scope adjustments, correctly the right direction, the first time.........well, at least that is the plan. Yeah I go the wrong way often and I go the wrong number of clicks sometimes but the plan is to shoot as little as possible to get on target at my desired POI.

    I actually just shoot one shot after each adjustment and if it lands as predicted, I adjust the other axis. I am trying to settle the scope adjustments, the same as tapping the scope. All adjustment turret assemblies move under recoil. The good ones return to the same place after the shot, the not so good ones do not. That adjustment assembly is suspended under spring tension and it will oscillate at each shot. We don't care as long as it comes to rest where it is supposed to. Certainly there are good scopes and better scopes and scopes not worth haulling home.

    Back home I have a large rock in the field, down the shooting range 300 yards away. After bore sighting I can stand offhand and fire one shot at this rock, calling the shot, and if I can see the impact, (I usually can) I can adjust the scope to hit the rock on the third shot. I've done it many times. I've won money doing it on a bet. I have failed to see the impact on the ground and not been successful and I've messed up the adjustment estimates and I've just plain missed the rock a few times, but generally it works out very well.

    I am often amazed at how many times folks will expend a box or more of ammo to try to get a gun on target.

    Some scopes have 1/4 or 1/2 MOA or 1/4" or 1/2" per click and many European scopes will have 1 cm (centimeter) per click (About .40"). These inch dimensions are based on a 100 yard distance, (the metric based on 100 meters) except with some handgun and rimfire scopes it may be 25 or 50 yards. I think where we go wrong and waste ammo is not knowing how far a click moves the POI. Also when we move some elevation and some windage at the same time they interact and (the turrrets really don't move the way they are supposed to) we make the correct number of clicks, but the interaction cause the reticle to go too far one way and not far enough with the other. Or some similar malady and we loose faith in are own clickology.

    I have mounted hundreds of scopes on other folks rifles and sighted them in, actually firing the gun with the loads, (usually my handloads) and when I do this I don't want to waste ammo or time as these jobs usually come in batches and everybody wants the gun back for hunting season. I needed to make this quick and painless. Back before we had lasers or even bore sighters or when folks don't want a gizmo screwed into the muzzle of their rifle by some minimum wage clerk at a big box store, we did things the old fashioned way. Maybe these new lasers have spoiled us and we've forgotten how to do it the old fashioned way.
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



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