The BFTA "British Field Target association" has an excellent tutorial concerning this subject as well as other valuable techniques. http://www.fekete-moro.hu/bfta-setup-manual/index-en.php#32
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How to find "optical zero" on your scope
- Thread starter Tominco
- Start date
Good discussion, here are the steps I take to optically zero a scope:
- The quick and easy way is to count the clicks from top to bottom then adjust to your mid-point (then you're done and move onto steps 1-5 below)
- Or, you can optically zero it using a small mirror to center your reticle within the housing. If it's not illuminated then you'll have to be near a window so light can reflect off the mirror into the scope.
- Set parallax to infinity
- Set magnification to medium/low
- Place scope flat on mirror
- Visually align the reticle & its reflection (the picture below shows them misaligned)
- Loosen the adjustable rings (snug but loose enough to move the scope by hand)
- Shoot gun on target at your desired zero distance
- Adjust the rear ring (up) until your pellets start hitting close to your zero distance
- Tighten all ring adjustments
- Finally, adjust your turrets to fine tune your zero
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Michael, I recently installed my first set of FX no limit rings on my WC. My question towards these adjustable rings, is what happens when you first go to sight in, and say, at 50 yards you are already hitting say 1/2” low from the bulls eye. Side to side(windage) doesn’t matter in this question. If these rings are purpose designed to take full advantage of you elevation clicks and not run out of elevation, what to do if your 50 yard shot is near zero, elevation wise?
Tominco, sorry to deter from your optical center tutorial. Thank you, btw. This mirror method is now all I use, thanks to Chuck as he explained it to me awhile back.
id like to add, that setting your scope to OC should be done even with new scopes out of the box. Two brand new scopes I recently purchased both said in their instructions that the scopes come OC from the factory. When using the mirror method, I found them both to be off slightly(like 5-10 clicks at both windage and elevation)
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I’m gonna ask this question to all on this tread to hopefully help others. If my assumption is wrong, let me know. I’m kind of piggy backing on NCED’s very beneficial link on the inner workings of a scope:
Is it safe to ASSUME, if turning turrets during a sight in session, if you see that your elevation corrections are affecting your windage settings(like meaning windage wise you’re already good to go, all you have left is to dial in the correct elevation to hit the bulls eye), that would mean your scope is most likely not optically centered? Of course, this could be vice versa also, where your elevation setting is good to go, and all you have to dial is windage, and in doing so it affects your elevation setting.
I ask this question because for years I struggled with sight in procedures, where every time I dialed one setting it affected the other. I knew nothing about having an optically centered scope. Then recently when I learned about OC my scopes, I notice once my windage was spot on, setting elevation didn’t affect the windage setting anymore.
Is it safe to ASSUME, if turning turrets during a sight in session, if you see that your elevation corrections are affecting your windage settings(like meaning windage wise you’re already good to go, all you have left is to dial in the correct elevation to hit the bulls eye), that would mean your scope is most likely not optically centered? Of course, this could be vice versa also, where your elevation setting is good to go, and all you have to dial is windage, and in doing so it affects your elevation setting.
I ask this question because for years I struggled with sight in procedures, where every time I dialed one setting it affected the other. I knew nothing about having an optically centered scope. Then recently when I learned about OC my scopes, I notice once my windage was spot on, setting elevation didn’t affect the windage setting anymore.
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This might help.........
https://www.youtube.com/watch?v=VeKUuY0yuCU
When I get a new scope it's normally optically centered from the vendor so the first thing I do is to check the reticle centering using the "mirror method". If the reticle reflected image of the new scope aligns with the the reticle within a couple clicks I consider the quick and simple "mirror method" of centering to be adequate.
After optically centering the scope it's mounted to the receiver, then I bend my barrel till the poi is within about 1" of the poa at 30 yards, then the fine adjustments are done via the turrets. Here is my home made barrel bending gizmo......
This contraption prevents the kinking of the barrel like the example in Joe's video, keeps all bending force off the pressed barrel to pivot block joint, and the Delrin insert spreads out the bending force so the barrel doesn't have a "kink" at the bend area. Also, the "barrel tweaker" makes it easy to reposition the "bending eye" (made from a 5/8" eye bolt) in the same position in case the bend is excessive to reverse the bend.......
As a side note, after using the "tweaker" to bend my .177 R9 or HW95 barrel enough to move the poi a few inches at only 18 yards the bend can't even be seen with the eye!
A while back I bought a new .177 HW95 barrel and after mounting it to my springer the barrel bending went like this using the optically centered scope......
https://www.youtube.com/watch?v=VeKUuY0yuCU
When I get a new scope it's normally optically centered from the vendor so the first thing I do is to check the reticle centering using the "mirror method". If the reticle reflected image of the new scope aligns with the the reticle within a couple clicks I consider the quick and simple "mirror method" of centering to be adequate.
After optically centering the scope it's mounted to the receiver, then I bend my barrel till the poi is within about 1" of the poa at 30 yards, then the fine adjustments are done via the turrets. Here is my home made barrel bending gizmo......
This contraption prevents the kinking of the barrel like the example in Joe's video, keeps all bending force off the pressed barrel to pivot block joint, and the Delrin insert spreads out the bending force so the barrel doesn't have a "kink" at the bend area. Also, the "barrel tweaker" makes it easy to reposition the "bending eye" (made from a 5/8" eye bolt) in the same position in case the bend is excessive to reverse the bend.......
As a side note, after using the "tweaker" to bend my .177 R9 or HW95 barrel enough to move the poi a few inches at only 18 yards the bend can't even be seen with the eye!
A while back I bought a new .177 HW95 barrel and after mounting it to my springer the barrel bending went like this using the optically centered scope......
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I've never bent barrels myself but that is an interesting device/method. I guess if it works then it works.
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If you use the mirror method this is what I did. I got a small round mirror, got about 10 for very little, and glued one to a scope cover. Tied a knot to use when scope is off of the gun or use the whole thing when scope is mounted. I use a very bright flashlight and it shows up very well. just my 2 cents worth, if its worth that.
Don
Don
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If you use the mirror method this is what I did. I got a small round mirror, got about 10 for very little, and glued one to a scope cover. Tied a knot to use when scope is off of the gun or use the whole thing when scope is mounted. I use a very bright flashlight and it shows up very well. just my 2 cents worth, if its worth that.
Don
That is absolutely worth every bit of a nickel! Seriously, its a great idea. Not a method I use myself but that seems to be a great setup for using the mirror method.
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NCED, I am not sure how your barrel bender works. Wouldn't it just make a "U" if the barrel is supported on either side? I have to correct a couple of break barrel springers and the MOA adjustment mounts are just not reliable enough to get on optical center.
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"Wouldn't it just make a "U" if the barrel is supported on either side?"
Yep, however if the barrel is bent enough to exceed the "elastic limit" of the steel a bit of the bend remains which repositions the muzzle enough to move the poi. Still....the bend that move the poi several inches at only 18 yards can't be seen. When bending a barrel I kinda "sneak up" on the poi I want with tiny adjustments of the eye bolt nut at a time. If the bend pushes the poi too far in one direction then it's rather easy to correct even though a bit tedious at times.
Here is an example of a target shot to judge the amount of bending required to get a suitable poi with a new .177 HW95 barrel. LOL, notice that the "1st group" shows the poi shifting from shooting pellets from a freshly cleaned barrel relative to the poi after a few "fouling shots" ................
The "blacked out number" was used as the aim point for all shots and the poi was shifted only with the barrel bends. This time it only required three "barrel bends" to get the poi where I wanted, however there are other times when it takes a lot more "adjustments/re-adjustments" to get the poi where needed. Also, as mentioned, the barrel bends are used only to get the poi within about 1" from the aim point at 30 yards using an optically centered scope. In the above target the poi was almost "dead on" the aiming point after 3 "bendings" at 18 yards which was real close to the aim point at 30 yards and the fine adjustments were done using "turrets".
Years ago I tried using adjustable scope mounts to adjust the poi but found that the procedure of "mounting scope", shoot a couple groups, take note of the poi, unmount the scope, move the scope saddles a bit, remount the scope, shoot a couple more groups, take note of the poi, unmount the scope so on and so forth till the poi was close to the aim point took (ME) a couple hours. After all that hassle I found that the tiny fiddly set screws holding the adjustment would "shake loose" after a couple thousand shots and then the whole TEDIOUS procedure had to be repeated. LOL.....what I ended up doing was adjusting the poi by simply bending my R9 barrel!
I got the idea of "barrel bending" from my brother because he slipped on a wet mossy West Virginia rocs and tossed his R9 "muzzle first" into another rock. That "rifle toss" moved his poi 3" at 30 yards, yet the gun was still accurate after some "turret adjusting". LOL...good thing he had a Beeman muzzle break on his gun because it kept his muzzle crown from being "messed up".
Yep, however if the barrel is bent enough to exceed the "elastic limit" of the steel a bit of the bend remains which repositions the muzzle enough to move the poi. Still....the bend that move the poi several inches at only 18 yards can't be seen. When bending a barrel I kinda "sneak up" on the poi I want with tiny adjustments of the eye bolt nut at a time. If the bend pushes the poi too far in one direction then it's rather easy to correct even though a bit tedious at times.
Here is an example of a target shot to judge the amount of bending required to get a suitable poi with a new .177 HW95 barrel. LOL, notice that the "1st group" shows the poi shifting from shooting pellets from a freshly cleaned barrel relative to the poi after a few "fouling shots" ................
The "blacked out number" was used as the aim point for all shots and the poi was shifted only with the barrel bends. This time it only required three "barrel bends" to get the poi where I wanted, however there are other times when it takes a lot more "adjustments/re-adjustments" to get the poi where needed. Also, as mentioned, the barrel bends are used only to get the poi within about 1" from the aim point at 30 yards using an optically centered scope. In the above target the poi was almost "dead on" the aiming point after 3 "bendings" at 18 yards which was real close to the aim point at 30 yards and the fine adjustments were done using "turrets".
Years ago I tried using adjustable scope mounts to adjust the poi but found that the procedure of "mounting scope", shoot a couple groups, take note of the poi, unmount the scope, move the scope saddles a bit, remount the scope, shoot a couple more groups, take note of the poi, unmount the scope so on and so forth till the poi was close to the aim point took (ME) a couple hours. After all that hassle I found that the tiny fiddly set screws holding the adjustment would "shake loose" after a couple thousand shots and then the whole TEDIOUS procedure had to be repeated. LOL.....what I ended up doing was adjusting the poi by simply bending my R9 barrel!
I got the idea of "barrel bending" from my brother because he slipped on a wet mossy West Virginia rocs and tossed his R9 "muzzle first" into another rock. That "rifle toss" moved his poi 3" at 30 yards, yet the gun was still accurate after some "turret adjusting". LOL...good thing he had a Beeman muzzle break on his gun because it kept his muzzle crown from being "messed up".
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Same here! I used a bright light on a mirror to align the reticle with the reflection for years, however recently I read about turning on the scope reticle lighting to get a reflection. Worked a treat when I tried it so the lighted reticle is always used for reticle setting.
After "optical centering" I also loosen the screws holding the "turret alignment marks", set them to zero "0", retighten the small screws, then replace the scope caps. This way I can always return to my optically centered settings if needed after doing the "fine adjustments" with the turrets..................
After "optical centering" I also loosen the screws holding the "turret alignment marks", set them to zero "0", retighten the small screws, then replace the scope caps. This way I can always return to my optically centered settings if needed after doing the "fine adjustments" with the turrets..................
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This is what a benchrest/ machinist friend showed me yrs ago, he took two 90deg. machinists blocks positioned them @ 45deg. so they were in a V then rotated the scope 360deg. Watching trough scope at crosshairs with a white paper background and adjusted turrets until there was no more run out! He did this on his leupold 36x and my Weaver-T36x, seemed to work fine? But yet br. Shooters don’t click or need the wide range of of adjustments as airgun FT Shooters & hunters need!
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That’s the method that Major John Plaster explained in his book “The Ultimate Sniper”. He explained to get a small shoe box and cut out exact shaped “V’s” at each end, lay the scope on the V, then rotate the scope back and forth. A scope not optically centered will show a elliptical shape cross hair instead of round. As you dial the turrets in the crosshairs come in toward the center and if done right, you will see a near perfect circle as you spin the scope back and forth on the V notches. At that point, you’re optically centered.
Well, I’ve tried that method, I’ve tried the count clicks and divide by two method, and the mirror method. The mirror method is my go to from now on. Simple, fast, and actually kinda cool to do. I thank Wildcat Chuck for turning me on to this method, and I’ll thank the folks on here for adding the idea of using the IR to see the cross hairs better.
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The video I made using the mirror was actually part of a series of videos. I covered the V-notch concept in one as well. I didn't use v-notches though. I just loosened up my scope rings.
Most of the time, I'll be using the mirror method as well. Quick, Easy, effective, and neat to look at too!
Tom
Most of the time, I'll be using the mirror method as well. Quick, Easy, effective, and neat to look at too!
Tom
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"lay the scope on the V, then rotate the scope back and forth."
The funny thing about both "spinning in vees" and "counting clicks, divide by two" is that those methods are only MECHANICALLY centering the reticle relative to the scope tube. This is especially true of the "count clicks, divide by two" method where it's assumed that the "click position from stop to stop" is centered to begin with. I'm guessing that with high zoot scopes (I never owned any) the alignment of mechanical components would be within tight tolerances, however I tend to doubt such "mechanical perfection" with the scopes I own. A while back I had a 4-12x40 Hawke Panorama and I "optically centered" that crappy scope using all three methods. Each time I took the scope to the mirror after a "different method of adjustment" the reticle reflection was in a different location....uh er QUADRANT! This made me wonder what method actually gave a true optical center which is why I started checking new scopes via "mirror method" before messing with the turrets.
The funny thing about both "spinning in vees" and "counting clicks, divide by two" is that those methods are only MECHANICALLY centering the reticle relative to the scope tube. This is especially true of the "count clicks, divide by two" method where it's assumed that the "click position from stop to stop" is centered to begin with. I'm guessing that with high zoot scopes (I never owned any) the alignment of mechanical components would be within tight tolerances, however I tend to doubt such "mechanical perfection" with the scopes I own. A while back I had a 4-12x40 Hawke Panorama and I "optically centered" that crappy scope using all three methods. Each time I took the scope to the mirror after a "different method of adjustment" the reticle reflection was in a different location....uh er QUADRANT! This made me wonder what method actually gave a true optical center which is why I started checking new scopes via "mirror method" before messing with the turrets.
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While this is a clever invention, I wouldn't count on it for zeroing. I've had scope caps, like those, that would easily sit canted to one side. In most cases, you can easily spot this but, if it happens pretty easily and regularly, then, maybe it's happening on a smaller scale that you can't pick up on as easily.
If you're going to try this method, then try this... Set it up and zero. Then, turn the cap/mirror 90degrees and see if it reads the same. If you're doing this with the scope on the rifle, there's a chance that gravity could be pulling the mirror out of square, unless your pressing on it. Another test to perform would be to remove the scope and caps and place the ocular bell directly on the mirror to see how things compare. This is the standard way of doing it because the body of the scope should be on the same plane as the scope's glass.
Tom
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