Seeing crosshair issue

[drcook]

I am new here, and new to to long range smokeless powder shooting. (I shoot long range BPCR with soule type iron sights) so I don't have the experience to fall back on or someone to ask this question of.

I was installing a scope on the rifle I am setting up for my wife. I leveled the rifle and scope with 3 different levels and actually checked the height of one of the levels using a dial indicator setup from my tool and die maker days and across 8" it is within .002 of being level.

When directly behind the scope, the crosshairs are perfect, but when I put the lower back on the rifle and subsequently my head and eye get "canted" I see the crosshairs as being off. If I move the crosshairs to what I see as vertical and horizontal, then the scope itself is way off, at a minimum 5 degrees, probably more.

I am going to acquire some of those levels that you put on the scopes to give a point of reference that I will be able to see when behind the gun. On my BPCR target rifles I actually have spirit levels attached to the front aperture sight (they are designed that way) because canting a rear vernier that is 3" tall can really throw the shot off. When looking through aperture sights, you just don't have anything other than that front level to give perspective.

The question is then: "does anyone else have this issue, or actually a something that is common ?" or am I experiencing a shift due to having an eye issue. I know that I have issues with my reading (and for that matter shooting) glasses shifting where I see things or even cause me to see double if the lenses aren't exactly aligned to each other. The last time I shot at 1000 yards I was missing badly and subsequently discovered that I was getting tremendous vision shift from the glasses I wore.

If I know whether this is a common issue or an issue that I am experiencing due to my unique way of seeing the world will help me formulate a plan to correct it.

Thanks!
dc

 

[MihiT]

It's my understanding that crosshairs should be aligned plumb to the bore, because that's how bullets fall.
If you're having trouble lining up you may need to raise/lower/ make a cheek rest.

 

[drcook]

Thank you for taking the time for answering, but that is not what I am asking.

I am asking if other people experience an optical shift in how the crosshairs are perceived based upon the position of their head changing or if it is just me having the perception problem which I can work at correcting.

I am setting the scope(s) up on AR platform .308's. Using the bottom of the upper, the barrel block that had its set screw "dimples" drilled at the factory (of course they could be off, but aren't), the table (which is level) and an adjustable 3 point rifle rest for the receiver end, the front end on a bipod, I leveled everything out and verified that the level I attached to the bottom of the receiver is parallel to the table top (within .002 in 8 inches, 90 degrees to the receiver). When I look through the back of the scope (straight on, not buttstock attached to rifle) the crosshairs are level and perpendicular, but when I shift around as when holding the rifle the "visual perception" of the crosshairs change and they look like they have moved.

All 3 levels agree, the one on top the scope turrets, the one on the bottom of the receiver and the one on the barrel block. All show being level. Visually the turrets look good also. If I wanted to get really anal about it, I could measure the diameter of the side focus knob, the diameter of the turret tube on the right side, figure the difference and check them. The mfg'er of the scopes that I use told us their tolerance is 1/3 of a degree. They are not inexpensive scopes.

I proved to myself (because of the types of work I have done all my life, I am very detail oriented) that the scope, the rifle and such are aligned as correct as they can be.

I think it is just me, but I had to ask if other people experience the same issue, and if so I would like to know how they resolved the issue.

 

[mike a]

Thank you for taking the time for answering, but that is not what I am asking.

I am asking if other people experience an optical shift in how the crosshairs are perceived based upon the position of their head changing or if it is just me having the perception problem which I can work at correcting.

I am setting the scope(s) up on AR platform .308's. Using the bottom of the upper, the barrel block that had its set screw "dimples" drilled at the factory (of course they could be off, but aren't), the table (which is level) and an adjustable 3 point rifle rest for the receiver end, the front end on a bipod, I leveled everything out and verified that the level I attached to the bottom of the receiver is parallel to the table top (within .002 in 8 inches, 90 degrees to the receiver). When I look through the back of the scope (straight on, not buttstock attached to rifle) the crosshairs are level and perpendicular, but when I shift around as when holding the rifle the "visual perception" of the crosshairs change and they look like they have moved.

All 3 levels agree, the one on top the scope turrets, the one on the bottom of the receiver and the one on the barrel block. All show being level. Visually the turrets look good also. If I wanted to get really anal about it, I could measure the diameter of the side focus knob, the diameter of the turret tube on the right side, figure the difference and check them. The mfg'er of the scopes that I use told us their tolerance is 1/3 of a degree. They are not inexpensive scopes.

I proved to myself (because of the types of work I have done all my life, I am very detail oriented) that the scope, the rifle and such are aligned as correct as they can be.

I think it is just me, but I had to ask if other people experience the same issue, and if so I would like to know how they resolved the issue.

This is why I have a bubble level on my scope. Nothing ever looks level to me!

 

[JMayo]

I can look at a target anyway I want but it better be straight with the leveled target edges ....

 

[drcook]

I put the stem of my dial indicator centered to the top turret so I would have a visual point of reference. It is my eye(s) interacting with cone of light coming out of the scope causing the shift. As I move my head I can see the reticles changing postion in relationship to the dial indicator. If I am directly behind the scope, all is well, but as I said, the crosshairs appear to rotate.

I have an appointment on Apr 25 to get cataracts looked at. Possibly they are causing an issue, I know for sure I cannot see under flourescent lights very well. I am not that old, 62, but I spent 28 years staring at a screen writing software. That didn't help my eyes at all.

 

[JohnKielly]

There have been occasions when crosshairs aren't plumb with the data points on the scope.

Try setting the scope up using a robust (heavy) plumb bob at a suitable distance while you have the rifle levelled up.

As to your question about optical perceptions, the foresight in a Garand bends to the right when I use my right eye, and to the left with my left, the same with an M14.

 

[msinc]

I think what you might be referring to is the difference between your eyes ability to see or seek level vs. the way you are holding your rifle. Holding the rifle is based on what "feels" comfortable to you and what feels comfortable is hard to accept that it's not "right". Right being the reticle set up level on the gun and level when you hold it, this is of course assuming that reticle {scope} is level on the rifle.
I barrel a lot of actions and in general mount even more scopes on rifles and shotguns. 99.9% of the time the customer shoulders his gun for the first time he invariably says, "you need to level this scope!!!". "The cross hairs are crooked!!". No, you need to change the way you are holding the rifle so they are level. Then I usually have to go thru showing the guy exactly how the scope is leveled to the rifle to even begin to convince him that the rifles right, he is wrong. I think this all goes back to an old saying that has been passed down for generations and is accepted as correct, until you are shown otherwise...next time you see a bunch of guys sitting around the table at deer camp listen when this subject comes up...one will eventually say, "everyone holds their gun different, so the scope on my gun will always look crooked to others..."

 

[drcook]

I am going to mount and work with a Nikon Monarch scope that I have and see if I get the same optical problem.

During a behind the scenes discussion with a board member, I realized I wasn't describing what is occurring exactly.

The image is rotating on the center point. The vertical line will go to 11 and 5 and the horizontal to 2 and 8 like turning a dial.

This is with the barreled action, sitting on a 3-point stand and the bipod on the front, with levels on the scope, attached to the base of the upper and on the forward gas block. All are level and the crosshairs are correct.

As long as I am positioned with my eye straight in line with the center line of the scope, all is well, but if I move my head, the cross hairs rotate.

It is not that I am mounting the gun wrong, I am not at all. It is what I am seeing.

I guess since no one has the same issue and is perceiving it as a leveling issue, it must be something I am just experiencing and will need to look into it when my eyes are checked.

 

[hrlincoln]

When directly behind the scope, the crosshairs are perfect, but when I put the lower back on the rifle and subsequently my head and eye get "canted" I see the crosshairs as being off.

You've pretty much answered your own question here. With no stock in the way and your head erect, the horizontal crosshair will appear horizontal. With the lower installed, you have to tilt your head slightly to acquire proper sight alignment in the eyebox. If you are shooting right handed and tilt your head to the right, the crosshair will appear as if it's rotated slightly counter-clockwise. Nothing abnormal about it. Custom stocks built with a cast-off or cast-on can minimize this effect.

 

[drcook]

"If you are shooting right handed and tilt your head to the right, the crosshair will appear as if it's rotated slightly counter-clockwise. Nothing abnormal about it.Custom stocks built with a cast-off or cast-on can minimize this effect."

Thanks. As I said in post one, I don't have the experience with scopes. The ones on my shotguns (Ohio used to be a shotgun for deer state) are very low power, and I really don't remember this issue with them.

If it is what is normally to be expected, then all is well.

 

[drcook]

I kept searching and actually found an old post on this, and some government research documents on the issue. It is a perception problem, not a leveling problem.

http://forum.accurateshooter.com/threads/my-reticle-appears-canted-to-me-its-not-why.3928472/

 

[elk3]

Shoot another rifle. Then you can see if its you or the rifle.
Good Luck

 

[Frostbite]

No it's not just you. I have the same problem. I wear progressive lens glasses and they cause all kinds of vision issues with both scopes & iron sights.
As soon as you tilt you head up or down or at a side ward angle you are looking thru a different curvature of your lens which either blurs your
vision or distorts the image. The old bent pencil in a glass of water trick. When you put your head on the cheek piece the tendency is to look
thru the upper left corner of your lens not the top center where your prescription is ground.

It helps to lay your cheek more on TOP of your cheek rest while keeping your head upright, instead of pressing your cheek on the side .
Getting a pair of glasses with only the far vision prescription seems to give a wider field of view before distorting.
Although that leads to problems seeing the sight adjustments.

Good Luck