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Sight Picture Troubles

Posted: Sat Jan 02, 2016 3:28 pm
by JPK
My daughter states she is now having problems determining if the target is in the middle. we have used Anshutz 3.7 - 4.0 18mm clear w/ bevel ring sized apertures.
Any ideas what to try?? I know your brain suppose to be able to that automatically. ???

Re: Sight Picture Troubles

Posted: Sat Jan 02, 2016 4:49 pm
by 1813benny
I would start with a check in with the eye doctor....

Re: Sight Picture Troubles

Posted: Sat Jan 02, 2016 5:07 pm
by moonlightrun
Can't she use a post in front instead of a circle?

Re: Sight Picture Troubles

Posted: Sat Jan 02, 2016 5:24 pm
by Pat McCoy
Try larger front aperture inserts. Many are finding (especially for offhand) that as big a 6mm or 7mm is the best choice.

Re: Sight Picture Troubles

Posted: Sat Jan 02, 2016 6:06 pm
by KennyB
Does she use a corrective lens?
How is her distance vision?
Indoors or outdoors?
Position/discipline?
Rear iris aperture size?

Do you have access to anything like SCATT or Noptel?

K.

Re: Sight Picture Troubles

Posted: Sat Jan 02, 2016 7:50 pm
by JPK
She recently has had a eye exam. No problems.
She just recently started using eye glasses instead of soft contacts when shooting.
She has a pretty good hold in standing averages 94/100.
Really do not want her changing to a post front sight.
We can try larger apertures but again she has no problem keeping targets in a 3.8 aperture.
I do wish we had access to a scatt and someone who knows how to analyze results, but we don't.
Just trying to save a little money and time and not have to start buying different front apertures (high contrast ,different colors, sizes...)
This has just come up since we started practicing indoors and only with her smb with clear, beveled apertures. No problems with air rifle with metal inserts. Rear aperture is the same on both rifles.

Re: Sight Picture Troubles

Posted: Sun Jan 03, 2016 5:14 am
by Tim S
So she can see a good sight picture (sharp foresight, and not sharp but not blurred target, and a good gap between these), but she can't determine when the target is centred? Does this only occur standing, or in other positions too? Have you tried a metal element as in the AIr Rifle if you know that this works? I've known very strong sunlight to wash out the ring from Perspex elements, but I've not come across this on indoor ranges.

There's no extension tube on the smallbore is there? The range of apertures you describe would seem OK for a standard length barrel in Prone, but add an 8in tube and there would be very little light betwen the foresight and target, especially in Standing.

Re: Sight Picture Troubles

Posted: Sun Jan 03, 2016 8:09 am
by efoleyjr
JPK wrote:My daughter states she is now having problems determining if the target is in the middle. we have used Anshutz 3.7 - 4.0 18mm clear w/ bevel ring sized apertures.
Any ideas what to try?? I know your brain suppose to be able to that automatically. ???
Sound like you need to try a "Centra Hi End glass aperture". The plastic may be causing problems.

Ed

Re: Sight Picture Troubles

Posted: Sun Jan 03, 2016 11:41 am
by redschietti
Go with what works in air! If she is wearing street glasses instead of contacts or shooting glasses that could be the whole problm

Re: Sight Picture Troubles

Posted: Sun Jan 03, 2016 2:21 pm
by KennyB
JPK wrote:This has just come up since we started practicing indoors and only with her smb with clear, beveled apertures. No problems with air rifle with metal inserts. Rear aperture is the same on both rifles.
Just a thought - is light able to get into the side of the perspex insert? On foresights that are deigned to take metal elements it's important to block off the slot that the metal element would drop into with a piece of electrical tape or similar.
Anschutz make a clip on plastic cover for this purpose:
Image Image

Allowing light in from the side can cause havoc with the appearance of the "ring" produced by the bevel.

Also it would be worth checking the rearsight aperture with a magnifier to check that a bit of fluff of hair hasn't gotten in there and is fouling things up... (been there).

K.

Re: Sight Picture Troubles

Posted: Sat Jan 16, 2016 12:49 pm
by imac
Hey try this

(sight radius (mm) × bull diameter (mm) ) ÷ distance (mm)

my smallbore rifle example
sight radius (include eye relief) = 934mm
50m issf target diameter = 112mm
target distance 50 meters = 50000mm
so 934 x 112 = 104608
104608 ÷ 50000 = 2.09mm

2.09mm is the apparent size of bull.
So multiple by 2 will give you 4.18mm
multiple by 1.5 will give you 3.15mm
I am slightly short sighted and I have a scatt which is great for testing these things
After a few hours I found that I am much better at centering the target with at least a 2 x apparent target size front sight.. Helpful I hope.

If air rifle is working for her

(sight radius x 30.5) ÷ 10000

Re: Sight Picture Troubles

Posted: Sat Jan 16, 2016 1:02 pm
by trax
KennyB wrote: Anschutz make a clip on plastic cover for this purpose:
Image Image
Another vote for having a shade over the front sight. I've got the exact same plastic hood on mine, because I frequently found that the floating aperture would disappear under certain lighting conditions.

Re: Sight Picture Troubles

Posted: Mon Jan 18, 2016 7:34 pm
by Andre
Is her cheek getting squished into the eye, and potentially causing unnatural astigmatism? I had this problem in the past, it caused the bull to become oval shaped and slightly blurry. Very frustrating.

Re: Sight Picture Troubles

Posted: Mon Jan 18, 2016 8:21 pm
by JPK
Looks like we solved the problem. The plastic insert with the beveled aperture did not create a very dark or wide ring. I purchased a "high contrast" insert and she seems to be happy with it. Thanks for everyone's suggestions.