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Vortex Viper PST reticle cant

 
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  #8  
Old 11-23-2013, 10:54 PM
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Re: Vortex Viper PST reticle cant

I agree, not worth messing with. I plan to check using plumb bob, but it has been so windy and cold here past few days I would have hard time just keeping plumb bob in the reticle! One way or another I highly doubt it would be enough to worry about if even there. You are correct that it could be that the windage knob is not a very good measure of vertical. I will look into it further when I get the opportunity but am happy for now.
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  #9  
Old 11-23-2013, 11:35 PM
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Re: Vortex Viper PST reticle cant

I don't want to sound condescending but, the levels you use probably aren't accurate in the first place. Keep in mind that checking errors are only as good as the initial accuracy of the first measurement and all subsequent measurements will compound by the inaccuracy of that initial measurement.

Consequently, I use levels that are accurate to within 0.005" per foot of lineal distance. That ain't a box store, internet gun supply house level. Those are very expensive machinery levelling levels, like 500 bucks each, with precision etched vials and lapped bases. If the indicator bubble(s) are centered, thats good enough for my eyes.

..and yes, all reticles can vary a few degrees from true vertical, thats a result of mass production and human error, no matter how much or little the scope costs.
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  #10  
Old 11-24-2013, 03:09 AM
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Quote:
Originally Posted by joeycoates View Post
Measured at about .3-.4 degree so I am not going to mess with it, not enough to worry about.
A reticle alignment error less than 0.5 degrees will not produce a significant aiming error, even at long range. That's easy to confirm using a ballistics calculator.

I regularly see reticle alignment errors of a over a degree. At 2 degrees the aiming error is becomes significant, and is comparable to spin drift.

If you're dialing elevation, then the anti-cant indicator should be aligned to the turret axis instead of the reticle. Then a small reticle misalignment really doesn't matter that much. As Crashman1 said, the best way to check that the elevation turret is plumb is to run the elevation turret up and down while looking through the scope at a plumb line. If the reticle moves left or right off the plumb line, the turret axis is not plumb. The rifle has to be held in a rigid vise when doing this.
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  #11  
Old 11-24-2013, 11:04 AM
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Re: Vortex Viper PST reticle cant

Thanks guys, pretty much what I figured as well. I would like to have a very accurate level, but I do not have machining equipment (although I would like to a some point) so for now I honestly would not have just a whole lot of use for it.
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  #12  
Old 11-24-2013, 11:47 AM
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Re: Vortex Viper PST reticle cant

Quote:
Originally Posted by joeycoates View Post
Thanks guys, pretty much what I figured as well. I would like to have a very accurate level, but I do not have machining equipment (although I would like to a some point) so for now I honestly would not have just a whole lot of use for it.
LS Starrett, Brown and Sharpe and Mitutoyo all produce high precision levels in analog (spirit vials with ground graduations) and digital master precision levels.

Typically, the analog levels are accurate to within 0.005" per foot od lineal measurement and the digital master levels will be accurate and repeatable to 0.001 per lineal foot.

The easiest way to ascertain if your level (or any level for that matter) is actually indicating properly is to place the level on a hard surface (like your countertop in the kitchen). It don't have to be square and level, it just needs to be smooth.

Place the level (any level) on the countertop and note the position of the bubble in relationship to the marks indicating the bubble is centered. The swap the ends 180 degrees (1/2 revolution) with the level comong to rest in the same exact spot on the countertop. Note the position of the bubble again in relationship to the marks. Any deviation of the bubble in relationship to the marks is how much the level is 'unlevel'.

You want to have the bubble centered between the indicating marks at the original position (of the level) and rotated 180 degrees. If it's not, the level will never give you a true indication of level or squareness as it relates to vertical plumb..... and the amount of deviation multiplies the error each time a secondary measurement is ascertained (like I stated in a previous post).

I regularly check my precision machinist levels using this method. All machinist levels are adjustable, that is the vial and it's carrier are mounted to the base in a manner that alloows you to adjust the vial to obtain repeatability.

Even a cheap, box store, cemented in vial can be adjusted, it just becomes more complex, either you release the vial from the cement and recement it with paper shims or you machine the base of the level by careful filing.

Always good to check, espceially a cheap box store level because chances are, it's not level in the first place.

You might think that door jamb is square (in relationship to the floor) but is it really? If you never checked the level when the jamb was installed, chances are it's not........

Gravity never lies......

BTW, in essence, thats how you 'tram' the spindle on a vertical milling machine to square the z axis to the x and y axis in relationship to the working surface. Thats neither here nor there however.
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  #13  
Old 11-28-2013, 09:14 AM
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Re: Vortex Viper PST reticle cant

Interesting
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  #14  
Old 12-11-2013, 01:01 AM
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Re: Vortex Viper PST reticle cant

Ya I agree, very interesting read! This is a great question, and I am learning a lot, guess its time for me to upgrade my levels....... Or have my smith use his....
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