Scope leveling idea

[thaught]

I have a bubble level app. On my phone, set my rifle in vice set my phone on the top rail and adjust till dead center level, tighten it and then set the scope on put the level on the turrets and adjust till dead on and tighten. The app is very sensitive to a hundredth of a degree

The turrets won't always be level is the problem. That is easy to prove. If you'll level the scope based on the flat underside, then turn the turret until it's level is the only way to do that. Sure you may get lucky, but I've never found that to be true. You have to turn the turrets some to get level

 

[Dirtrax]

I built my own one of those using a piece of 1/4" 6061-T6 and a circular bubble level from McMaster and a 12" long section of pictinny rail from amazon. Three M6 hex heads, two in opposing corners and the opposite centered between the corners level the plate. After screwing it all together I used an electronic level to confirm both that the bubble level was correct and that the top of the rail was parallel to the top of the 6061 plate. Almost took longer to describe the build than to do it. I have the Wheeler levels, not too impressed with them. I bought the Arisaka leveling tool and will get to try it soon.

I still owe the forum a pic of the tool that I used to use and need to make another one of. Picture a piece of clear plexiglas bent in a sharp 90°. It is the width of the bolt raceways and has a vertical line scribed in it. Remove the bolt and place the tool on the raceways. Look through the tool at the retical. Rotate the scope until the vertical reference in the retical is parallel to the scribed line. Tighten the scope.

If the bore is not directly under the vertical reference in the retical, that is to say if the bore centerline and the vertical post or reference in the retical are not in the same vertical plane then as the distance increases windage error creeps in. Not long ago someone here put it better than I'm managing right now. You can make the POA and the POI agree for one distance when they are not coplanar, but when the distance changes the POA laterally moves away from the POI. When they are coplanar then excluding any wind influence the ballistic arc of the projectile's path is also coplanar and you get no distance induced "windage" error.

If the NPA (Natural Point of Aim?) hold is skewing the rifle off vertical then the rifle needs an adjustable butt to get it vertical while in the NPA hold.

The bore is a circle and circles have no inherent level. When a repeatable Natural Point of Aim (NPA) with no forcing of the rifle maintains solid recoil management how can that affect down range performance assuming that the scope is true to gravity and perpendicular? I've tall target tested and cannot find an issue. I completely understand why an optic that isn't "true" will skew things. That's why we use anti-cant levels. The erector needs to travel straight up and down. Isn't this movement relative to gravity and not the rifle? Of course I could be completely wrong.

 

[Rflshootr]

Why not just invest in one of these

View attachment 212339

BADGER ORDNANCE - DEAD LEVEL SCOPE LEVELING DEVICE

1. Because they cost too much.
2. They only work with pic rail type set up.
3. I can fire lots of ammo for the same cost.
4. Who says the tapped holes on top of the action are dead square and exactly on the centerline?
5.

 

[Jeffpatton00]

The bore is a circle and circles have no inherent level. When a repeatable Natural Point of Aim (NPA) with no forcing of the rifle maintains solid recoil management how can that affect down range performance assuming that the scope is true to gravity and perpendicular? I've tall target tested and cannot find an issue. I completely understand why an optic that isn't "true" will skew things. That's why we use anti-cant levels. The erector needs to travel straight up and down. Isn't this movement relative to gravity and not the rifle? Of course I could be completely wrong.

You're right, circles have no inherent level. However, they do have a centerpoint. You say "... the scope is true to gravity and perpendicular" and here's where I get confused, because we seem to be dealing with multiple (and potentially erroneous) definitions of "perpendicular". As a thought test, imagine a setup where the scope is rotated a little, and if you extended the reticle's vertical axis, it would miss the bore's centerline. When you shoot you could unconsciously rotate the rifle slightly and the scope's vertical axis would be perpendicular to gravity, as you mentioned, but out of alignment with rifle's bore. The more elevation you apply to the scope, the further off the POI would get. It seems to be that the only requirement for scope leveling is to get the reticle's vertical axis to pass through the bore's centerpoint, and absent problems with scope tracking, all POI changes will occur along this line. Again, I'm testing my understanding, am I missing something key here?

 

[RSRW]

I was having trouble with getting level off the turrets, so I called Vortex. They advised to use the plumb line method. Just what Vortex said. They told me that in many cases the turret tops are not perfectly level.

 

[ntsqd]

The bore is a circle and circles have no inherent level. When a repeatable Natural Point of Aim (NPA) with no forcing of the rifle maintains solid recoil management how can that affect down range performance assuming that the scope is true to gravity and perpendicular? I've tall target tested and cannot find an issue. I completely understand why an optic that isn't "true" will skew things. That's why we use anti-cant levels. The erector needs to travel straight up and down. Isn't this movement relative to gravity and not the rifle? Of course I could be completely wrong.

The bore is a cylinder, which means that it has a center-line. Then we put a scope on the rifle above the bore. It has horizontal and vertical references along with the center-line of it's tube. There is a stock and how that fits the shooter sets the angle relationship between the shooter and everything else. One of those reference lines in the scope must ideally intersect the bore center-line. If the scope is directly above the bore, but the horizontal/vertical refs are not "square" then a windage error occurs with changes in distance. This is why offset scope mounts are not very favorable.

Now if we rotate the rifle and rotate the scope within it's mounts so that even though the rifle is not "level" but the reticle is aligned such that it's vertical component, when extended beyond the scope itsell, will intersect the bore center-line, then we have the best bore - scope alignment. Even if the anti-can't says that the rifle is 30° from level.

Put differently, what level intends to achieve is that the bore center-line, the vertical reference of the reticle and the projectile's trajectory are ALL in the same plane, and that plane is set by gravity. Visualize a bullet's flight path with no wind influence. Now orient yourself relative to it such that it appears as just the straight line. It will be vertical. The bore center-line and the vertical part of the retical, when viewed form that same position, should all be aligned with that straight line. They can be anywhere along that line and it extensions either up or down.
If they are not, then you get a horizontal error when the target distance changes.

 

[Dirtrax]

You're right, circles have no inherent level. However, they do have a centerpoint. You say "... the scope is true to gravity and perpendicular" and here's where I get confused, because we seem to be dealing with multiple (and potentially erroneous) definitions of "perpendicular". As a thought test, imagine a setup where the scope is rotated a little, and if you extended the reticle's vertical axis, it would miss the bore's centerline. When you shoot you could unconsciously rotate the rifle slightly and the scope's vertical axis would be perpendicular to gravity, as you mentioned, but out of alignment with rifle's bore. The more elevation you apply to the scope, the further off the POI would get. It seems to be that the only requirement for scope leveling is to get the reticle's vertical axis to pass through the bore's centerpoint, and absent problems with scope tracking, all POI changes will occur along this line. Again, I'm testing my understanding, am I missing something key here?

Thank you for that cogent response.
I will note that I do indeed try to level the scope to the rifle but with little tooling to absolutely ensure bore/scope continuity. So I do what I can and don't fret about what I can't yet accomplish. The results have been very good so far.

 

[Varmint Hunter]

The problem I have with understanding everyone's comments is that so many of them describe referencing "level" off mechanical features of the rifle or scope, like the rifle's pic rail or the scope's bottom or turret top. It seems to me than none of these are important, so maybe I'm missing something that you all see. However, it strikes me that only 2 reference lines are important in scope leveling: 1) an invisible vertical "dotted line", running from the center of the barrel to the center of the scope. All elevation adjustments will be along this line, but leveling the rifle off the top of the pic rail may be way out of plumb with respect to this line. So, making certain this line is truly plumb sets the rifle's level. I haven't done this but I'd imagine hanging a plumb line off a wall, then looking down the rifle's bore to ensure the plumb line is visually "centered" in the bore as much as possible, then rotate the rifle (in a vise or other fixture) until the reticle's center point is exactly centered on the plumb line (while the bore remains centered on the line), and at this point we've set the rifle's level. 2) The scope's reticle must then be made plumb to the rifle/scope plumb line by carefully rotating the scope, within the rings, until the reticle's vertical axis is perfectly aligned with the distant plumb line. This should be confirmed via a tall target test.

I'm hoping to simplify the scope leveling process for my simple mind, rather than make things more complex. Am I making a fundamental error in my thinking above? It all seems to get down to what it means to level the rifle, and I think setting the rifle's level off a mechanical feature like the pic rail means that we have to make a lot of assumptions: the pic rail is square to the barrel rather than slightly higher on one side or the other, or the scope's Mfr made the scope's bottom or turret top square to the elevation's line of action, etc. We should be able to avoid all those assumptions by simply aligning the rifle's "vertical" to this line between the bore's and the scope's centerlines. What do you think?
Jeff

I totally agree with you on this. My question is, how can you get "an invisible vertical "dotted line", running from the center of the barrel to the center of the scope? If you achieve this than you can just put a barrel mounted level on the rifle so that you could move to the next step. I had an aluminum tool that had two V sections that sat on the scope and on the barrel. It also had a small level. In a perfect world this would seem to be the solution but it never seemed to be accurate.
My smith works off the feed rails but that has nothing to do with aligning the centerline of the bore with the centerline of the optic.
I've set my scopes up using various technics and then tried to verify what I've done by checking with levels placed on the rails, pic base, scope caps, etc and they never agree.

I can easily tell when the reticle is perfectly plumb because I used a 6' precision level to mark the backboard at 400yds. Then I staple my white targets right down the line. But ... when the reticle is held perfectly plumb; is the rifle perfectly level? Probably not. I've gotta try a box test.

 

[Jeffpatton00]

If you're nailing small varmints at 400 yards or more, sounds like you're well on your way to a good setup.

 

[Mram10us]

Whatever method you use, do a tall target test to verify. Best of luck

 

[milo-2]

Why not just invest in one of these

View attachment 212339

BADGER ORDNANCE - DEAD LEVEL SCOPE LEVELING DEVICE



Since I have slowly switched to using picatinny rails, this is on my to buy list. I have used the plumb line method with decent results, but it always leaves me struggling with cant induced by tightening the caps.

Interesting tool, and should work. But for 159 I will continue to use the shutters on my neighbor's house across the street.

 

[Jeffpatton00]

Interesting tool, and should work. But for 159 I will continue to use the shutters on my neighbor's house across the street.

And we'd still be assuming that the top surface of the rifle's pic rail was perfectly manufactured to be perpendicular to that center-to-center line between the scope and bore. However, since the pic rail is some distance above the bore's centerline, any cant at all will introduce windage, and that'll be amplified at longer distance. I do think that if I hang a plumb line, have the reticle's vertical axis perfectly superimposed on that plumb line, and also have the plumb line bisect the image as seen through the bore, then we'd be measuring the critical parameters directly without making assumptions about things done right (or wrong) in the rifle or scope manufacturing processes.

 

[WahooYahoo]

Nothing is perfect. Its a reference point. If the plane across the pic rail is level and the scope turret is level and a plumb line correlates with the vertical crosshair, then call it level. The 1/xx Moa tilt that is not accounted for is insignificant at best.

 

[Dirtrax]

It sounds like many of you are reaching the same conclusion I came too, namely that perfection is not readily attainable. So...do what's possible today, the impossible will take a little longer. Cheers!