I have a shooter who has a an interesting sighting issue. When the shooter looks through the rear sight they don't see a nice round circle. The part that is out of round is around the 4 o'clock region and covers about 20% of the opening. The first thing I did was to look through the sight. OK, it is nice and round even while adjusting the iris through its range. Even though the shooter uses a blinder I asked them to close the non-aiming eye. My thought was some cross-dominant issues. Nothing changed when the non aiming eye was shut. This happend in all 3 positions. Their head position is so that they look straight out their eye, no big head tilt downward so that they are looking past their eyebrow.
This shooter is no beginner, averages in the 580's 3P smallbore, shot above 590 in air. They have had a recent eye exam over the summer, no astigmatism as far as that goes. Wears contacts while shooting and has said problem has been around a long time. I guess they just learned to work around it. I'm looking for any ideas? Thanks
Rick
Odd sight picture problem - any ideas?
Moderators: pilkguns, Marcus, m1963, David Levene, Spencer
It is more straight than oblong. I'm going to continue my interrogation today for more details. I agree with you that the cheekpiece could be an issue causing the shooter to not look through the sights correctly but the level of shooter make me think that it can't be that. Top level competitor. Could be though? I"ll give it a try.
Interesting problem, I would be inclined to investigate the "optical" route although I would ensure that all the basics; cheekpiece/looking through the centre of the aperture; are covered as well.
It would be useful if you could investigate whether the phenomenon was present when looking through a lens of similar prescription to the shooter's contacts. For this you would probably need a shooting aware optician and if it didn't work you certainly would. I would also quiz the shooter about whether they had described this problem to their optician and what their response was. This may also give some clues.
Whatever the outcome please keep us posted. I am very interested, having undergone quite extensive eye surgery over the years eyesight has become a "thing" with me.
Rutty
It would be useful if you could investigate whether the phenomenon was present when looking through a lens of similar prescription to the shooter's contacts. For this you would probably need a shooting aware optician and if it didn't work you certainly would. I would also quiz the shooter about whether they had described this problem to their optician and what their response was. This may also give some clues.
Whatever the outcome please keep us posted. I am very interested, having undergone quite extensive eye surgery over the years eyesight has become a "thing" with me.
Rutty
We have enough shooters who wear corrective glasses on the team. I bet I can find someone with a similar prescription. I have no experience with contacts but I do know that she switched types of contacts over the summer. However, the problem was present with both types. Ill try getting some glasses on her tomorrow.
I asked her today if it happens with her air rifle. She said that it was not as bad which makes me wonder what is going on even more. I looked through the sights and did not see anything mechanically wrong with them. Also, I do not think there is any misalignment with her head/cheekpiece position that would cause this. This was for smallbore not airgun. We havent shot that since I've been working on this issue.
I'll post more when I know more. Thanks for the help.
Rick
I asked her today if it happens with her air rifle. She said that it was not as bad which makes me wonder what is going on even more. I looked through the sights and did not see anything mechanically wrong with them. Also, I do not think there is any misalignment with her head/cheekpiece position that would cause this. This was for smallbore not airgun. We havent shot that since I've been working on this issue.
I'll post more when I know more. Thanks for the help.
Rick
FWIW I have terrible vision (-9.75R, -10.25L plus astigmatism) and experienced the same problem a few years back.sbrmike wrote:If the "out of round" is flat, the shooter is not looking straight through the sight. It probably needs the cheekpiece adjusted.
If it is oblong, I don't have a clue; sounds like a vision problem for an Optometrist to solve.
It turned out that it was my head position and cheekpiece. I raised my cheekpiece so my head was more upright and I was looking through the optical center of my eye and then I added riser blocks to move my sights up to match. Voila -- no more "out of round" sight picture.
Posting a side-on picture would also help us help you out.
Jason
Provided the shooter is consistent in head position and the error is consistent, then there is no reason for the shooter to not perform, however, it will be easier to correctly line up sights if the shooter corrects the problem as more light will get through the site.rjjr wrote:It is more straight than oblong. I'm going to continue my interrogation today for more details. I agree with you that the cheekpiece could be an issue causing the shooter to not look through the sights correctly but the level of shooter make me think that it can't be that. Top level competitor. Could be though? I"ll give it a try.
OK, todays update:
I had her draw me a picture of what she is seeing. Instead of a circle it looks like almost complete circle, like a day or so after a full moon.
I then had her look through the sights to verify it was still there in Kneeling, yesterday was standing, it was. I asked her to look without the cheekpiece and move her head around to get the best sight picture. The problem persisted wherever her head was able to see through the iris. I kind of think that this eliminates any cheekpiece problems. I've attached a pic of her in kneeling.
I then asked her to adjust the iris while in position and seeing the problem. Cheekpiece was installed this time. She described it as: the iris got bigger/smaller but the dark area stayed the same. OK, this led me to change to a completely different rear sight thinking it was something blocking a clear sight picture. Same thing with an old-school 1980's Anschutz sight.
Odd, no?
Rick
I had her draw me a picture of what she is seeing. Instead of a circle it looks like almost complete circle, like a day or so after a full moon.
I then had her look through the sights to verify it was still there in Kneeling, yesterday was standing, it was. I asked her to look without the cheekpiece and move her head around to get the best sight picture. The problem persisted wherever her head was able to see through the iris. I kind of think that this eliminates any cheekpiece problems. I've attached a pic of her in kneeling.
I then asked her to adjust the iris while in position and seeing the problem. Cheekpiece was installed this time. She described it as: the iris got bigger/smaller but the dark area stayed the same. OK, this led me to change to a completely different rear sight thinking it was something blocking a clear sight picture. Same thing with an old-school 1980's Anschutz sight.
Odd, no?
Rick
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Is it the whole picture which has this flat on it? I mean, does she see a round target with a flat inside a black ring with a flat?
If so, does the target still have a flat when she looks at it not through the sights? Just with her aiming eye? With both eyes?
My best guess would be astigmatism, but it is only a guess. Does her optician know she shoots? Just for normal everyday life they don't always worry about minor variations if it would turn a simple cheap prescription into a complex expensive one (for instance I used to have a lens prescription which I only used for shooting. I couldn't actually see any difference at all using the lens. But my eyes didn't get as tired.)
If so, does the target still have a flat when she looks at it not through the sights? Just with her aiming eye? With both eyes?
My best guess would be astigmatism, but it is only a guess. Does her optician know she shoots? Just for normal everyday life they don't always worry about minor variations if it would turn a simple cheap prescription into a complex expensive one (for instance I used to have a lens prescription which I only used for shooting. I couldn't actually see any difference at all using the lens. But my eyes didn't get as tired.)
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Levergun59
- Posts: 251
- Joined: Thu Nov 18, 2010 1:37 am
- Location: Silver Lake WI
She definitely needs to see an opthamologist. I would have her quickly look at the round dot of an aimpoint. I have astigmatism and I didn't see a round ball. The eye doctor worked with a pair of glasses by adjusting the frames and then added diopters until I saw a round ball. There is a condition my mom has where two veins have fused and ruptured in front of her retina. She has peripheral vision but mostly a black center in her vision. See the doc. Also one more thing. I have seen a mirror thet screws into the rear sight to correctly position the eyeball dead center. Trick is, I can't find it now. Hope this helps.
Chris
Chris
Go to Home Depot tool dept. and buy a tool mirror, cheap, and take mirror out of holder. Then tape it to the rear eyepiece. It will save you a ton of money and do the job.Levergun59 wrote:She definitely needs to see an opthamologist. I would have her quickly look at the round dot of an aimpoint. I have astigmatism and I didn't see a round ball. The eye doctor worked with a pair of glasses by adjusting the frames and then added diopters until I saw a round ball. There is a condition my mom has where two veins have fused and ruptured in front of her retina. She has peripheral vision but mostly a black center in her vision. See the doc. Also one more thing. I have seen a mirror thet screws into the rear sight to correctly position the eyeball dead center. Trick is, I can't find it now. Hope this helps.
Chris
Ed
Odd Eye picture
Try this trick. Make a small hole in a card about 1mm diameter. (1/16 inch or so for you USAers.)
Looking straight ahead, hold this card about 50mm from the eye. With another card, and while keeping the bottom of it horizontal, slowly move it down while holding it against your eyebrow. Eventually it should begin to oclude the hole in the other card. A shadow will start to creep across the hole from BELOW if you do it slowly and correctly.
Does the shooter see this?
If so, then I would bet that either her eyelid or eyebrow is creating this same effect. The reason it comes from below is that the eye sees an inverted image and the hole in the card is acting like a pin hole camera. Just like the back sight does.
Either get the shooter to open her eyes more, or lift the head more so that the eyebrow is out of the line of sight. Sometimes if the line of sight comes close to the nose the same thing happens.
Looking straight ahead, hold this card about 50mm from the eye. With another card, and while keeping the bottom of it horizontal, slowly move it down while holding it against your eyebrow. Eventually it should begin to oclude the hole in the other card. A shadow will start to creep across the hole from BELOW if you do it slowly and correctly.
Does the shooter see this?
If so, then I would bet that either her eyelid or eyebrow is creating this same effect. The reason it comes from below is that the eye sees an inverted image and the hole in the card is acting like a pin hole camera. Just like the back sight does.
Either get the shooter to open her eyes more, or lift the head more so that the eyebrow is out of the line of sight. Sometimes if the line of sight comes close to the nose the same thing happens.
Like most others I think its an eye condition that needs expert checking from a specialist opthalmic consultant, idealy one who shoots, and explain the circumstances that it is for shooting.
There are not many things in normal life where you look with great concentration through a pin hole at a dot for hours on end so few consultants would consider such an effect of interest.
Just as a desparate stab in the dark, has she tried less eye relief?, her head is upright but have you tried bring back the sights?
Best of luck, let us know what it was when it is fixed.
Robin
There are not many things in normal life where you look with great concentration through a pin hole at a dot for hours on end so few consultants would consider such an effect of interest.
Just as a desparate stab in the dark, has she tried less eye relief?, her head is upright but have you tried bring back the sights?
Best of luck, let us know what it was when it is fixed.
Robin