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Bore & Scope Alignment

Forums General Airgunning Bore & Scope Alignment

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    josh3rd
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    Ok members, I know that a scopes vertical crrosshair is supposed to bisect the center of the barrel to eliminate cant. You can use a plumb line to make sure your scope is straight up and down. 

    What I want to know is how can you make sure that your rifle is straight? I know that if you have a breach block or a weaver rail, you can set a level on it but what if you don’t have anything flat on your rifle to lay a level on? 

    For instance I have a prosport with a blk bubble level that attaches to the scope tube. When I look through it at a plumb line, the scope and bubble level shows true but the rifle stock feels crooked. Ok so when I pull my face back to the rear, behind the butt pad and see a very small circle opening through the scope, i center the crosshairs and make sure the bubble level is in the middle, I can see the bottom of the crosshairs post kinda at the 5 o’clock position. 

    My whole point is that when looking at a target with the rifle is in the shooting sticks or shouldered, and the bubble level is level, the crosshairs look just a little crooked. Even if I am looking at a plumb line and the crosshairs are straight with the line, it looks like the bottom is at 5 o’clock and the top at 11 o’clock. 
    Now unless it’s windy, my shots are right on the vertical for the most part from 10-55yds. 

    Is there a way to check a prosport to see if it’s level (right/left)? I tried to place a torpedo level underneath because that is the only flat place.

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    sirk
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    If your barrel is pointing left or right, only a hammer can fix it. LOL
    Look if your barrel in not straight, does not matter if the action and the stock are straight, or even the scope housing or its erector tube.
    You can mess around forever with your scope turrets or mounts, it will never get right.
    you are saying it is to the right all the time, why dont you adjust the windage then? if your crosshairs are not vertical then adjust the scope rotation too with the plumb line.
    if you cant hold it straight true, no point adjusting it on the table. As long as you know where the shot will go you can even hold it upside down, keep it shooting more you will get to know it better.
     

    • This reply was modified 2 months ago by sirk.
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    josh3rd
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    All I am saying is that when I hold the rifle and put the scope’s vertical crosshair on the Plumb line I put on a Target and my scope Bubble Level reads true, it looks like the top post is tilted to the left as to if I hold the rifle to what feels normal to me, it don’t line up with the plumbed vertical line I drew.

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    sirk
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    how does it shoot/behave when benchrested. 
    I see you are saying the natural position/confortable one is not the one what puts the gun to perfect vertical alignement. Yes unfortunately i have the same problem, i guess because our shoulders and arms etc are not square lol
    i think it is normal.

    just try to get it right whatever works for you best, as close as possible to ideal position. we all have to work on the form

    • This reply was modified 2 months ago by sirk.
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    josh3rd
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    Yeah you’re probably right. It shoots great and how it should. I just don’t like how it feels and looks.

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    sirk
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    there are bubble levels what you can fasten/clamp to your barrel too, something like this
    https://www.midwayusa.com/product/1009244912/wheeler-engineering-professional-reticle-leveling-system
    so if you have one on the barrel and simultaneously one one the top of the turret or so, you can align all to the plumb line. in my experience too, i have not seen one gun what fits me 100%

     you will get used to it if it shoots straight

    • This reply was modified 2 months ago by sirk.
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    Scotchmo
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    “josh3rd”
    My whole point is that when looking at a target with the rifle is in the shooting sticks or shouldered, and the bubble level is level, the crosshairs look just a little crooked. Even if I am looking at a plumb line and the crosshairs are straight with the line, it looks like the bottom is at 5 o’clock and the top at 11 o’clock. 
    Now unless it’s windy, my shots are right on the vertical for the most part from 10-55yds. 

     

    
 If your shots are on vertical from 10-55yds, then everything is setup correctly, and you are not canting the gun.

    For most setups, you must tilt your head to the right (right handed shooters) when looking through the scope. That makes the reticle appear canted to the left (ccw) in relation to your head/eyes. Eventually your brain adjusts and it looks normal. I tilt my head severely when in the seated FT position. It was a little disconcerting at first as everything looked sideways. Your mind adapts with practice.

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    josh3rd
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    I never knew about the tilting of the head. Thanks brother. 

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    ncstan
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    The way I set up a scope is to put the rifle in a rifle vice take the top off of the scope ring and attach the base of the scope rings to the rifle.Put a bubble level on top of the rings and level by adjusting rifle in the vice.put the top of the rings on and lightly tighten rings..put the level on top of the elevation turret and level the scope…Then You will have the rifle and scope level.You can use a string bob instead of leveling the scope.But I find leveling the scope easier.If You try to level the scope with a string bob on a unlevel scope base You will have a cant in Your alignment.The small aperture that You are seeing is caused by improper eye relief..

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    Alan
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    This is the tool I use:

    https://www.amazon.com/Arisaka-Optic-Leveler-Combo/dp/B00W8AXZ98/ref=sr_1_5?ie=UTF8&qid=1505339221&sr=8-5&keywords=scope+leveling+tool

    Worth the $35 I paid many times over. And no level needed!

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    josh3rd
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    That is a good idea Alan but one would need a one piece mount or weaver rail which a prosport doesn’t have

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    josh3rd
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    Good idea ncstan. Also the small aperture I was talking about is when I take my face off the rifle and put my head behind the butt pad and just kinda eyeball how the reticle is oriented towards the center of my action.

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    Scotchmo
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    “ncstan”The way I set up a scope is to put the rifle in a rifle vice take the top off of the scope ring and attach the base of the scope rings to the rifle.Put a bubble level on top of the rings and level by adjusting rifle in the vice.put the top of the rings on and lightly tighten rings..put the level on top of the elevation turret and level the scope…Then You will have the rifle and scope level.You can use a string bob instead of leveling the scope.But I find leveling the scope easier.If You try to level the scope with a string bob on a unlevel scope base You will have a cant in Your alignment.The small aperture that You are seeing is caused by improper eye relief..

    
ncstan,
    Your method puts you at the mercy of the engineering/manufacturing tolerances. It might be good enough for some but most guns will benefit from setting the reticle/bore alignment instead.

    In order to have the trajectory always lie on the vertical reticle, the scope must be rotated in the mounts such that the reticle intersects the bore. And then the reticle must be held perpendicular to earth when shooting via a scope mounted bubble level.

    The reciever, scope mounts, or turret caps aren’t usually perfectly level. If they do end up being level after a proper setup, you got lucky with the tolerance stack. But I would never base my setup on them.

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    peterdulux
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    http://www.brownells.com/gunsmith-tools-supplies/sight-scope-installation-tools/scope-reticle-levelers/vertical-reticle-instrument-prod6097.aspx

    Works every time

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    josh3rd
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    Let me borrow yours😉

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    Grin_Reaver
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    “josh3rd”
    What I want to know is how can you make sure that your rifle is straight? 

    
Step 1 would be not having your head horizontal. Not only is it distracting but also you can not keep track of straightness of stuff in the vertical plane. 😉

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    josh3rd
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    Grin_reaver, just out of curiosity, why would my head be horizontal? I hope I didn’t say that anywhere and got people confused.

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    ncstan
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    Scotchmo when I said that I leveled the scope by a bubble level on top if the elevation turret obviously I rotated the scope to level it..There is some deviation in turret covers and the level base .But I have cross referenced this setup with a plumb bob and it is always very close.Is My way a perfect way to set up a scope NO ! But it is a simple way with a small investment to accurately set up a scope.That being said I am in the process of equipping My new addition to My family a Barnes DM ar15 300 black out.This article has got me thinking about using a carpenter’s laser plumb to set up the alignment of scope .I also will check the alignment of a couple of My rifles using the stated method of alignment.

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    cosmic
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    Also don’t forget a lot of stocks have cast off… ( stock is not perfectly straight and slightly bent right or left..)

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