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How critical is scope level?

I have a kit that I put together myself that works incredible. contact [email protected] if you want to know more...
I guess what I'm looking for is a similar thing to progressing from a bubble level on the elevation turret cap to a plumb line at 100 yards kind of thing, only to level the rifle. All that said, if the math is correct, it's way more critical to hold the rifle level than to have it perfectly level when you mount the scope.
 
Most everyone understands that the crosshairs on a scope and barrel center vertical alignment are ultra critical for shooting longe range. My question is this. If you have a scope height of 1.75" above barrel center, in a perfect world, how much would 1 degree of left or right cant while shooting effect point of impact at 1000yds? 1 degree in 1.75" is .031". Perfect world, no elements

Thanks
 
I guess what I'm looking for is a similar thing to progressing from a bubble level on the elevation turret cap to a plumb line at 100 yards kind of thing, only to level the rifle. All that said, if the math is correct, it's way more critical to hold the rifle level than to have it perfectly level when you mount the scope.

The critical part is that the center of the barrel and the center of the scope have to be vertical first. I have atool that i use that levels the bolt lugs (which levels the rifle) and I use an expensive precision machinist level, not a plastic one. Accuracy within .0005. Then I align the scope vertical with the string/plumb bob in a tree at 100yds. Tighten the ring bolt very slowly and carefully.
 
The best way to understand is to look at a scope canted 90 degrees.if you are zeroed at 100 yards and have a 2" scope height you will be off only 2" at 200 and 18" at 1000 yards and that is the most it can be off. That's at 90 degrees of canted reticle. Drop that to 3 degrees and you can see it's pretty insignificant. This only applies to the scope to bore axis not general scope cant.
 
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The critical part is that the center of the barrel and the center of the scope have to be vertical first. I have atool that i use that levels the bolt lugs (which levels the rifle) and I use an expensive precision machinist level, not a plastic one. Accuracy within .0005. Then I align the scope vertical with the string/plumb bob in a tree at 100yds. Tighten the ring bolt very slowly and carefully.

the bolt lug races on the action I should clarify...
 
Most everyone understands that the crosshairs on a scope and barrel center vertical alignment are ultra critical for shooting longe range. My question is this. If you have a scope height of 1.75" above barrel center, in a perfect world, how much would 1 degree of left or right cant while shooting effect point of impact at 1000yds? 1 degree in 1.75" is .031". Perfect world, no elements

Thanks
For a perfect level scope = no change.
 
SEE? I knew there was a reason to get the Talley top half ring with bubble level on my Browning X-Bolt Pro scope mount.

Actually I'm used to using a level on my Ruger Precision Rifle for competition and figured I wanted to use a very compact level on my hunting rifle. Talley makes very nice stuff. My rings are even burnt bronze Cerakoted to match my rifle. ("Matchy, matchy", ya know)

Eric B.

BTW, getting that Talley bubble level top half ring to be exactly level on a leveled rifle was not fun! Tightening the 4 ring screws to get it level required a lot if slow tightening. Then when fairly snug I criss-crossed the tightening sequence with my inch/pound torque wrench to 17 in./lb. and re-checked level. Had to loosen once and re-start the sequence all over but got it the second time.
 
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Shoot it the way you shoot it best, and learn how to deal with any side effect of your hold. One of America's Palma Team members and holder of several NRA Hipower records in the 80's and 90's always canted his gun, but learned how to deal with it. That's not to say I (or HE) endorsed shooting that way; its just to say that the best position for YOU may well overcome any sight adjustment quirks that result.
 
I too use a plumb bob to get a vertical reference for the cross hairs. You can look through the bore to see that the plumb line bisects the bore, then set your level bubble. Check with tall target.
Here is how I think of scope vs. POI. The rifle shoots where it shoots; we try to get the scope to cover the POI. If you rotate the scope to the right, clockwise, the cross hair is to the right of the POI. If you then move the scope to the hoped for POI, bullet goes to the LEFT of where you aimed.
 
Most everyone understands that the crosshairs on a scope and barrel center vertical alignment are ultra critical for shooting longe range. My question is this. If you have a scope height of 1.75" above barrel center, in a perfect world, how much would 1 degree of left or right cant while shooting effect point of impact at 1000yds? 1 degree in 1.75" is .031". Perfect world, no elements

Thanks
Check out my video on rifle cant.

 
This is awesome, thank you for sharing. Will use this to illustrate importance to my customers during the mount and bore sight process.
I really question this canting? I see Hill Country Rifles shootinq at targets over 2 miles and watching them, it doesn't seem they could possibly be conscious of or looking at their level. Yet they are hitting the target consistently.
 
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