Bull disappearing in prone position

usmcmba · Post by **usmcmba** » Tue Feb 17, 2009 8:14 pm

Hi List,

I am relatively new to high power shooting and lately I have found that on the last relay (20 rounds in prone at 600 yards), around half way through the relay, it becomes very difficult for me to focus on the bull (the black). As a matter of fact, I have noticed the bull start to "disappear" (or turn to light gray) as I am in the prone position for a length of time, usually around 10 mins.

I have 20/20 vision. I shoot adjustable iris for rear and front sight. I have tried to close my eyes in attempts to eliminate the eye strain when this condition starts to happen, this does work in making the bull black again, but only for a very short period of time. I have also tried to change the iris settings but do not seem to help.

Does anyone know of something else to try besides closing the eye or focusing on a fixed point to ease eye strain. Also does the use of a color filter or polarizing filter help?

Thank you in advance for any advice.

David

usmcmba · Post by **usmcmba** » Tue Feb 17, 2009 8:20 pm

By the way, I forgot to mention that this condition only occurs while I am shooting in the prone and not the offhand or sitting. Also, I only have a anti-glare tube in the front sight but not rear, would adding such help at all?

Thanks all!

jackh · Post by **jackh** » Wed Feb 18, 2009 1:48 am

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xcrunner8k · Post by **xcrunner8k** » Wed Feb 18, 2009 9:36 pm

my father had this problem in smallbore; the problem was he had lost diopters at close range (accommodation) and couldn't focus on the front sight when it was 32 inches away. he put a 10-inch extension tube on the gun and now the problem is gone.

which brings me to question #1, if you don't mind me asking: how old are you? as you age and particularly after 40 your eye loses focus at close range, even though you would still be able to see well at other distances. my dad's eyes are asymmetrical; he uses a Champion shooting lens with a very mild distance lens on his shooting eye and a reading lens on the other eye so that he can read the sights and score targets.

if you are not middle-aged, well then i think it would be an issue with light coming into the eye. try allowing as much light as possible into both eyes but not so much that everything is washed out. if you have the hat with the flaps, get rid of it. use a blinder just small enough to hide the target from your non-shooting eye. open up the rear sight a little, and try different front ring sizes.

dan

JamesH · Post by **JamesH** » Thu Feb 19, 2009 7:04 am

Lack of oxygen to the eyes?
Lying prone and holding your breath for extended periods has a cumulative effect.
Try hyperventilating a bit.

methosb · Post by **methosb** » Thu Feb 19, 2009 7:33 am

Possibly pushing your cheek too hard against the cheek piece? Your cheek could be pushing up against your eye.