In this issue:

Re: Astigmatism (long)
Re: High Standard Victor trigger
Re: Rifle shooting glasses
Crosman International Airgun Championship
Re: BRNO TAU7
Re: Rifle torque settings
How to use polarizers?
Eyes and dominant mental entity (long)

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Astigmatism doesn't interfere with target aquisition. You can always adjust
your rear sight for correction of position. Astigmatism shifts the whole
image of your sight it does not blur it.
But if you are wearing prescription glasses you MUST wear your shooting
glasses at least half an hour for giving your eye the time to adjust for not
using a lens to correct its problem.
I am using this for 5 years now after the advice of my doctor and optician
(they are shooters too) and after discussing it with the guys at Champion I
am convinced that this is the right way.
You can use a lens with astigmatism but you must be sure that it will stay
ALWAYS at the same position as any change will result to a different sight
angle.
As you may know most of the shooting glasses are round and they are fixed in
one side only so you will always have one more worry if the lens is in front
of your eye at the same distance and not shifted in its round frame. If you
are going to add an astigmatism lens then ask from your optician to mark the
lens and the frame for position reference.

[Editor - I asked for a more detailed explanation of his above comments and
this is George's reply.]

Draw a circle and an eclipse with the same center (to make it easier).

Imagine the horizontal diameter of the circle and the horizonal diameter of
the eclipse. Imagine now that the longest diameter of the eclipse is NOT
vertical or parallel to the horizontal diameter of the circle.
The view of your sights will be shifted from the true position. Try now to
understand it with the center shifted too.

Check the image that I've sent you. You will see that although when your eye
is Ok , the sights are over the target when you see an elipse you will aim
more below and right.

Calculate now the different vertical plane of the rear sight, the plane of
the front and the far away plane of the target. You have more than four
planes (the first is your eye and lens - two planes but close to each
other- ) shifted and distracted. The distraction in astigmatism is not
progressional but logarithmic.  In theory only when the width of the rear
slot (or circle for rifles), the width of the front sight and the projection
of the target are the same, your astigmatism is +/-90 degrees, your shooting
position is always exactly the same you will NOT have a LARGE distraction.
But this is theory and never occurs.

The worst thing that can happen for a shooter is to have astigmatism. Of
course if you have it then your luck is for +/-90 degrees problem.

Short sighting is just blurring in any field and angle of view and you can
see through many (well not so many!!) points of the prescription lens (as
long as you are trying to see through the center of it). In astigmatism any
point other than the exact center of the lens (and sometimes the optician
misplace the center or the angle of the lens) you will see a different sight
and you will not know it. Add to this the difference between shooting
sessions-rounds and you can understand that the minor shiftings add to a
major problem. It is like having a rear sight that changes clicks from round
to round!!!

That is the true reason for not using astigmatism lenses on your shooting
glasses. To diminish the whole problem by deleting at least one stage of it.
But if you are going to use a correction lens you must add at least a peep
sight or an iris for locating the exact center and adjust permanetly the
shooting glasses frame, your rear sight and use always the same shooting
position. To difficult for most of us. Without the astigmatism lens you have
only to deal with the shifting of your sights (corrected with the adjustable
sights).
As you can imagine this is not true for large amounts of astigmatism. In
these cases the use of a lens is a must as the distraction is too much but
until now I don't know even one shooter with lots of astigmatism. Most of us
have no more than 2 points.

And you must know that most eyeglass wearers develop by time slight
astigmatism. The main reason is the force on the eye to adjust and dirty
glasses (even sunglasses with zero correction)!! This means that although
you examined your eyes a month ago your astigmatism may have slight
variations.

BTW using an iris will broaden your field of depth. This means that (as in
photography) you will focus in more planes than with bare eye.

The true reason of using adjustable sights is mainly the difference between
the roundness of two persons eyes. How many times did you try to shoot a
rifle or a pistol of a friend just to find out that you must correct for
more than 4-5 clicks left-right or up-down. The gun shoots straight, the
roundness of  your eyes is different. Of course there are also other reasons
for using adjustable sights but this is one of the most important ones.

I am sorry that I can not explain it using more scientific language but
English is not my native language and I am not an eye doctor.
But I have the problem and I love to shoot so I was forced to find out and
understand the way of correcting it.

I have two good friends and shooters into the science, One is the president
of the Greek opticians and the other is an eye doctor (professor in the
Greek Med. University). We did a lot of talking about it and I've spent
hours talking with the guys of CHAMPION-BRILLEN at Nurnberg this year.

I believe that every shooter with astigmatism must understand how to correct
its problem. I was shooting 560-565 before understanding my real problem.
Now I shoot 570-575 with no astigmatism lens ( and of course corrected
sights). This means that 10 nines became 10 tens.

I am always here for every question and I love to discuss about our sport.

Thank you for providing the shooting community with such an interesting and
informative site and mailing list.

George Giamarellos

Intl. Chief Range Officer for pistol UIT and IPSC shooting
Gunsmith for Hammerlis (not by profession)
Eyeglass wearer from 12 y/o (now 38)------>  8o)

PS. I will be happy if you visit my site "Greek Shooting Pages"
http://users.otenet.gr/~g2
It is in Greek and I am sure you will not understand a word (even for us
Greeks sometimes it gets too difficult!!) but it is the only Greek site for
shooting and my provider gives me only 1Mb of space. Mainly pistol.

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>From your description of the difference I would say the problem is in the
trigger bar disconnector point with the sear. As the editor said, it could
be dirt in this area. It could be mechanical... Not enough free play when
the trigger is held back to reset to the same depth as the first cock.
Remove the left grip and work the slide by hand while observing the bar. It
should snap up the same distance and hook the sear exactly the same with
each cocking of the hammer whether the trigger is depressed or not. 

A less likely factor (based on your description) is too much clearance in
the sear pin to frame hole. A new and/or oversize pin will correct this.
Another frequent problem is in the trigger pull adjusting mechanism...
Either the screw moves or the spring between the screw and sear is
misplaced or loose. I can help you off line after you make these
observations.
Dave Salyer    salyer@126.com

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Re the comments on eye glasses, corrections and things. it is a good
response isn't it! The subject seems to have hit a nerve.

My thoughts are that the 'old school shooters' insisted to their grave that
the foresight has to be in focus. Period. From the time I started shooting
I have never shot with the foresight sharp. When I did try it out I just
saw an incredibly blurred bull. This old school also insisted that the
sight picture can be sharpened by closing the backsight. The pin hole
effect. Unfortunately the size of the hole gets too small and it really
clouds over and blocks the light - but I concede that the image of the
sight and bull is sharper. Shame that it is too dark though. The purpose of
the back sight is to enable you to line up the sights with the bull. The
pin hole sharpens it up a little bit but there is no way both foresight and
target are going to be in focus at the same time. My experience as to the
most effective picture is when both target abd foresight are at an equal
level of fuzzyness. That is, the eye is focused at some point between the
foresight and the target. I suspect that it is around 5 metres or so out.

Which brings me to bloop tubes. It was obvious to me when these things
arrived  the big advantage was that the foresight and target are brought
into focus more than with the standard setup. I suspect the the eye is then
focused a little more than 5 metres out. (To the human eye 6m appears close
to infinity) Thus the longer the better theory. I suspect that the
mechanics of  "front heavy" rifles brought the extensions to an abrupt end.
It seems that about 400mm seems to be about the handiest length to
manipulate. Don't forget that people stand and kneel to shoot as well so
extra long lengths have a tendency to wave about more in the breeze, thus
nullifying the advantages a little bit. 

Glasses. Big or small.  Can you see the flags with a small one? If not then
a bigger size wil help. Especially if things are blurry without glasses.
Lining a big lens up can be done with a friend. Get them to make sure it is
perpendicular and centred over the back sight.

What size back sight to use? My rule of thumb is to set it so that there is
a clear hole in the middle that just covers the foresight. If the back
sight is opened up from about 0.8mm it remains 'hairy' until about 1.0mm.
>From then on a clear hole emerges that progressively gives a clean picture
through it. It apears that 1.1 to 1.2mm is almost a universal size for
backsights. Funny that.

Another interesting funny thing to note is that the clear hole that emerges
does not always appear in the middle of the backsight. Mine appears a
fraction high. Others see it low. It 'could' be an aspect of design of the
backsight but I suspect that it is just genetics at work. 

We are children of the universe and all different. We just relate multiple
versions of reality to each other. Vive la difference! 

Tip for the day - EXPERIMENT!

Ross Mason
Scientific & Laboratory Instrument Servicing

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I'd like to post an announcement of an Air Rifle/ Air Pistol  Open
competition in Toronto, Canada next Feb 5/6/7, 1999.
It is called the Crosman International Airgun Championship and is
ISSF,(UIT) designated as a 'Grand Prix'. 
There is a double course of fire, i.e. 2x60 or 2x40 as per event. The
Championship is shot at a hotel close to the International airport. Room
rates are CDN$84, single or double.
For information and event information, contact ohahq@netrover.com.
Snail @ Ontario Handgun Assoc., 2055 Dundas Street East, Unit 105,
Mississauga, Ontario, Canada L4X 2V9
Last year there were over 280 participants from 5 countries competing.

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I am a long time .45 auto shooter who has recently taken up UIT Airgun.
I presently shoot the Tau 7.  I just finished the latest mailing list
which had answers to the question how many shoots per 12gm CO2 bulb does
one get with the Tau 7.  The answer depends on the power setting.  My
pistol, with the velocity set at 445fps, gets about 100 full power
shots.  When set to 500fps the pistol gets about 40 full power shots.
Presently I have my pistol set at 460fps which yields about 65 to 70
full power shots.  In a match I start with a full charge, take my warmup
shots, shoot 30 shots then dump any remaining CO2 and recharge.  This
method yields most consistant results.

Also, I have designed a pair of little rubber stoppers that allow the
Tau 7 to be dry fired.  I have attached the instructions for anyone that
is interested.
 <<Dry Fire.bmp>> 
Lanning R. Hochhauser
lanningh@datair.com

[Editor - please contact Lanning directly if you wish to see his drawing. I
didn't think everyone would like me to send an attachment.]

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Regards: Torque

Gentlemen:

	This is my first time responding to a topic as well.  Essentially
when tuning a rifle, there seems to be two major trains of thought.  One
relies on the rifle and the other the ammunition.  Handloaders are
notorious for spending hours working up loads to make the most accurate
ammunition.  As the smallbore shooter does not easily have this option,
the tuning of the rifle is the key.  "Torqueing" or adjusting the tension
on the bedding screws affects the harmonics of the barrel, and thus
affects the time in which the bullet leaves the barrel.  If the period and
the vibration are consistant a nice "round" hole is formed.  At the
University, we have started doing this for not only each rifle but
whenever we receive a large change over in the lot of ammunition being
shot.  We start at a low setting and commence tightening screws
alternately and firing groups.  Whether in inch pounds or newtons it
doesn't matter.  But we have been able to get a little more accuracy out
of our rifles using this method.  And in many cases, the torque settings
the rifle(s) are most accurate at do not match front to back.  Hope I
wasn't too wordy.

David Lee
NDCS coach / USF rifle coach

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Can you please post a question on the adjustment technique for the rear
sight polarisers.  I am not sure if it is important to use both polarisers
vs. one polariser? 

Thanks, Eitan 
Eitan@ytd.com 

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THE PHYSICAL EYE AND THE COGNITIVE ENTITY...

A visual analyzer consisting of the eyes and visual center of the dominant
mental entity are most important to the shooting athlete.   The refractive
abilities of the eye is altered by the action of the ciliary muscle.   This
is possible because of the elasticity of the eye's lens. The accommodation
reflex allows the eye to focus on objects positioned  at varying distances.
However, the eye cannot  maintain a simultaneous clear image of objects
positioned at different distances in space.  During the aiming process,
under the old military method of shooting, the eye must accommodate three
different objects, the target, front sight, and the rear sight.  Only one of
the three images will be observed and in focus at any one time.   The
remaining objects will be diffused images on the retina.  The eye
accommodates rapidly from one point or object to the next, fixing each
object clearly in about .0001 to .0004 of a second, in effect one object
will be in focus and the other two will appear as hazy or fuzzy images, on
the retina at any one time.  The dominant mental analyzer must analyze and
interpret the three images on the retina simultaneously at the time period
indicated above for each image.  The analysis function can be accomplished
in focus or out of  focus.

Upon receipt of the images by the visual analysis center of the dominant
mental entity, a massive analysis and interpretation phase is accomplished
by the dominant mental element of the cognitive entity.  Upon the
determination by the dominant mental analysis center that the image or
information received through the eye is important, such as the image of the
bull down range in relation to the front and rear sights is not detected as
the perfect bull's-eye, the information is passed to the non-dominant mental
entity for interpretation and issuance of instructions to the neuromuscular
system for adjustments or physical realignment of muscles necessary to
accomplish the corrected bull's-eye alignment.  Through mental practice and
dryfire training sessions, the shooting athlete will learn to limit the eye
or reduce accommodation actions to the front sight only and therewith
ignoring the hazy or fuzzy image of the target now held in the mental
analysis entity.  It is very important that the shooting athlete understand
the only image required to be in focus is the front sight as the other
images can and will be analyzed as fuzzy objects without focus.  Any of the
images can be brought into focus by spontaneously placing attention upon the
image desired in focus.  As the shooting athlete places spontaneous
attention upon any one of the images the images becomes focused and clear
to the dominant mental entity through the use of ciliary muscle
accommodation. The shooting athlete can stop eye fatigue by placing
spontaneous attention upon the front sight.   The athlete must be very
careful not to stare at the front sight as this will cause fixation and
bright reflected light will over stimulate the retina, causing visual
hallucinations and reduction of the
eyes sensitivity.  A small movement of the eye from side to side will
eliminate this action of the eye.

However, this conditioning can breakdown under stress by the shooting
athlete.  Our natural instinct is to look at the 'bull' we intend to fire
upon with our rifle/pistol, not at the rifle/pistol itself or its sights.
This natural instinct tends to emerge at the dominant mental level and its
effect will be noted after a bad shot has been fired. The physical eye and
retina accommodation between the target, front sight, and the rear sight is
the major cause of eye fatigue and shooting athlete's failure to obtain
consistent shooting results.   In bright sun light the bull's-eye on the
target appears smaller than in dull light.  The reason is that when an area
of the retina is strongly stimulated by the bright light, the area of
stimulation tends to overflow into the surrounding areas of the retina
causing enlargement of the image formed by the bright area of the target.
This effect makes the black bull appear smaller.  This also affects the
point of aim, which is higher in bright light and lower in cloudy conditions
or dull light.

Fatigue will slow down the eye accommodation reflex, making it very
difficult to bring the sights into focus.  The best method for relaxing the
accommodative system is to relax the ciliary muscles themselves by reducing
the necessity of the ciliary muscles to accommodate multi-images during the
shooting and sighting process.  This reduction in effect is accomplished by
only focusing upon the front sight while allowing the rear sight and bull to
remain in the background and in unfocused alignment with the front sight.
The bull remains a fuzzy image and is aligned through the use of the bright
white light in the front sight. Bright reflected light can be controlled
through the use of a dark or gray tinted lens. During dull or overcast
conditions a yellow or red lens will enhance contrast. The non-dominant
mental entity produces the mental pictorial representation of the perfect
bull's-eye for use as the point of reference by the non-dominant and
neuromuscular system adjustments during the sighting process.

The analysis phase compares the physical eye perception of the fuzzy bull in
alignment with the  front sight while the non-dominant mental entity uses
the pictorial representation of the perfect bull's-eye as the index model
for the adjustment in relation to the pictorial representation of the
physical bull as detected by the physical eye.  Upon the determination that
the two pictorial representations are identical in every respect the
non-dominant mental entity directs the Mental Checklist to continue with the
analysis phase and firing process.

Extracted from Chapter 8 and Appendix C of the book.

Chet Skinner, Coach
cskinner@dol.net
http://www.geocities.com/Colosseum/Midfield/1245

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End of UIT Mailing List #11

Michael Ray - Systems Engineer
Rose-Hulman Inst. of Tech. Rifle Coach
UIT Shooting Page - http://www.geocities.com/Colosseum/1190/index.htm