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In this issue:
List format change
Re: USA Shooting Coaches College
Re: mats
Re: mats
Re: Poor eyesight problems
Re: Air rifle scoring puzzle
S&B ammo / torque settings
Re: Need kneeling help
Re: Need kneeling help
Need items for stuff for sale list
Zero changes between positions
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Sorry for any confusion that the recent change from eGroups to Yahoo may have caused those of you that have signed up for the "real-time" version. I had no idea that such a merger had even taken place back in August and didn't know they switched the site over until I went to login an hour ago. Imagine my surprise.
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Re: Coaches College at OTC
We do not have an approval, but we have asked for the 15-18 of November
with alternate weekends backward from there. We won't get an approval
until about May.
Martin Edmondson
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Why do most smallbore shooters buy mats which resemble a domestic
mattress? Do we need to pay for the major padding in the lower three
quarters of the mat? Some people lack my natural padding around the
middle area :-) , so may get sore hips from digging into concrete fp's -
fair enough. But the extra padding adds massively to unit weight and
bulk (air travel, carrying to ranges).
The hard rubber on most mats I have seen in UK & elsewhere plays havoc
with soft rubber elbow pads on most jackets - expensive to buy a mat
which will make new elbow pads necessary.
The mat I bought for under 50 pounds sterling has good padding (but not
VERY cushion-like) under elbow 'quarter' and gradually thinner on lower
quarters, reducing weight and folded bulk. Waterproof underneath but not
on top. Soft grip material (similar in design to Thune) which does not
erode elbows. Available from John Carmichael, UK (in whose Company I
have no financial interest).
Patrick Jess, St Andrews, Scotland
[Editor - I emailed Mr. Carmichael and received the following reply.]
Dear Michael
Your e-mail address gives no indication of which country you are in, so I
will assume you are probably not UK.
I do such a mat, but not at less than half the price!
Prices are as follows:
Shooting Mats JHC Supplies
ISU/ISSF 4 Panel Full Size 2.0m x 0.8m each �81.70 nett
TR 4 Panel Padded Full length 1.725m x 0.685m each �46.81 nett
TR 4 Panel Part Padded Full length 1.725m x 0.685m each �42.55 nett
TR Short Padded Top panel only 0.5m x 0.685m each �24.68 nett
TR Groundsheet Roll up 1.75 m x .711m each �25.53 nett
Prices are ex works UK and do not include postage which varies according to
the order size & method of despatch.
The first one is very similar to the Thune mat, but slightly wider (the Thune
mat is narrower (0.78m) than the specified width of 0.8m!!). It folds up the
same way and fastens with Velcro. The top panel is covered in "Gripfast"
rubber which I use on all my mats and which is far superior to the Top Grip
rubber used by Thune & Anschutz, the pattern being similar to luggage
conveyor rubber.
All the others are TR (Target Rifle) mats.
I do not have an electronic picture of this mat.
Regards
John Carmichael
JHC Supplies
e-mail: [email protected]
[Editor - does anyone know the rationale behind the ISSF rule specifying an MINIMUM size for mats? Seems odd that it MUST be at least 80x200cm.]
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If your shooting mat needs help - pull the backing off of a computer mouse pad and glue it on the mat. Works Great!
J.D. Hicks
Microsoft Gun Club ( no joke - it is really a club here )
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Steve Podleski wrote:
> I have a problem in centering the front sight in the rear sight. Many
> days I see what I think is the penumbra in the rear sight; I need to place
> my eye on the edge of the rear sight iris to see 'around' this shadow (or
> region of no image) to see the front sight and this penumbra seems to move
> during a string or disappear. Am I doing something wrong?
1. There is a difference between a "peep" sight and a "ghost ring" sight.
The difference is the size of the hole you are looking through. As long as
the rear sight hole is larger than the pupil of the eye, this is a ghost
ring and it is the pupil that determines where you are looking from. If the
pupil of the eye is not in the exact same position each time, preferably in
the center of the ring, then the sight angle will be different and the gun
cannot be aimed accurately. A target sight with a large, bright rear
aperture can act as a ghost ring even though it looks like a peep sight.
If the sight hole is smaller than the eye pupil, regardless how little
smaller, then this is a peep sight and it is fundamentally different. As
long as the eye pupil includes the entire sight hole, the position of the
eye pupil has no effect and the line if sight will be exactly the same every
time. The area around the front sight might appear different, i.e. you might
have more light on the left side one time and more on the right side another
time, but this will have no effect on the target at the center of the front
sight.
Again, that is only as long as the entire peep hole is included within the
pupil, when measured in direct line of sight from the target or the front
sight. If the peep hole drifts so far to one side that some of the light
through it is cut off by the side of the pupil, then the line of sight will
begin to go crooked as it is constrained between the (for example) right
edge of the peep hole and the left edge of the pupil. But as long as the
entire peep hole is included within the pupil, which should be indicated by
maximum brightness of the target (given the size peep hole selected, which
will cause a dim target compared to a larger peep hole), then eye position
does not matter and the line of sight will always be the same.
The point is that one should always use the smallest peep hole possible that
still gives adequate brightness. The smaller the hole, the less critical is
eye position. If this is done correctly, the line of sight will always be
correct and the only limiting factor will be the position of the target in
the front sight. Notice this is not a good/better/best type of accuracy, it
is absolute; either the entire peep hole is included within the pupil (which
is completely perfect), or part of it is not (which is unacceptable).
2. Anything that partly blocks the light path within its limiting hole, will
cause an out-of-round appearance in the sight picture. Normally if you
partly close your upper eyelid (no gun), you will see the vision blockage at
the top. However when looking through a peep hole that is smaller than the
pupil, the blockage will begin at the opposite side! Because only the top of
the eye sees down through the peep hole (bottom part of the overall image),
and only the bottom of the eye sees up through the peep hole (top part of
the image); then the upper eye lid partly blocking the pupil will block the
Bottom part of the image, opposite the usual effect!
The problem I get, is that pushing my cheek on the stock will push my lower
eyelid too high. This causes a dark shadow at the Top of the image. It is
difficult to remember that everything is inverted from normal so that I can
correctly identify the problem in order to fix it!
If you see a shadow blocking one side of your image, you need to carefully
check anything that might be blocking the OTHER side of your eye! This could
be glasses frames, your cheek, your hair, or anything else between your eye
and the peep hole. The correct problem is often not as obvious as you would
think, because of the inverted image. When the entire pupil is properly
exposed to light from the entire peep hole, you should see a round image
through the peep hole; otherwise there is something that needs to be
corrected before shooting. As long as the image is round and the front sight
and target are anywhere near the middle, the front sight will correctly
indicate bullet placement on the target.
- Benjamin McLeod
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Hi Michael,
Jeroen Hogema Writes about where the 11 disappears to?
It is only an 11 if the bullet hits the dead centre. One could argue that the centre of the bullet hole never (rarely anyway) hits the exact centre of the target. Thus a 10.9 is the best one can do. In effect any decimal score eg 10.9 or 9.7 is 0.25mm wide whereas an 11.0 is infinitely small.
Interestingly, I have been doing some work with working out the patterns and scatter of fullbore target shooting (because of the Trentham Range Closure problem) and found some interesting results. If one plots the distance from the centre the shot hits (in effect what decimal scoring is) versus frequency, you suddenly discover that the greatest number hit at a distance from the centre.
Here are the numbers: (I had collected about 1200 shots from the NZ National 300m Chanpionship, so you can work out the percentages if you want)
0 to 1cm 13
1 to 2 76
2 to 3 162
3 to 4 150
4 to 5 197
5 to 6 175
6 to 7 120
7 to 8 116
and on and on.....
So the greatest number appeared around 3 to 6 cm from the bull. It will be the same for any form of target shooting that uses circular bulls. I suspect that the number of 10.9's, 10.8's, etc will follow a distribution like this. Hmmm....I hadn't thought of that until just now...I must check it out!!! Must go check Finals scores over a few Championships!!
BUT: When the data is plotted as a density function, that is, divide the number of shots within each division by the area (circle for 0 to 1cm, and annulus for everything else) then the density is greatest in the middle.
Hope that clears a few things up.
Regards
Ross Mason
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Our club has acquired a ton of new small-bore bullets. They are 0.22lr SB Club by Sellier & Bellot. A Czech company, which I am sure, a lot of the readers are familiar with. Has anyone had any experience with them and how do they rate?
In some recent mails there was mention of torque settings. Can anyone suggest the relation of this torque with the velocity and does one move up or down. These S&B bullets seem to be a bit higher in velocity than we expected and I was wondering if there is a general rule of thumb for it.
Any information will be of great assistance.
Great shooting all!
Usman (Pakistan)
[email protected]
[Editor - I doubt torque has any effect upon velocity. It only has a potential effects upon accuracy as the barrel harmonics change with different torques.]
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Notes on the kneeling position pictured.
(I see) Right sholder lower than left.
Eyes not level as seen from front view.
Question if right heel is directly at base of spine or on puffy
part of cheek.
Paul Menjik.
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The subject is Guido's kneeling position.
Top left picture; the left foot is the problem, to far forward. Because of
this forward placement the elbow to knee relationship is incorrect, the head
will move out of position. With the head out of position the resultant eye
to rear sight orientation is incorrect.
Right foot and knee appears correctly placed. Right arm appear to be
correctly placed and the right hand is OK although the trigger finger is
rapped to far around the trigger.
Sling appears OK and correct height. Left hand appears to far forward
again the hand stop.
Recommended adjustments to position.
1. Move the left foot backward so the heel and instep is directly under the
knee.
2. This will cause the required adjustment to the elbow/knee relationship.
The elbow should be place on the forward edge of the knee and just to the
right of the kneecap.
3. This will cause an adjustment of the left hand stop position (move back
towards the center of balance point) and sling adjustments as necessary.
4. All of the adjustments will force the head return to the straight up and
down position and therefore correct placement of the eye to rear sight
relationship.
5. One last item that should be looked at is the shoulder alignment. The
rifle/shoulder contact is a bit out of the correct angle. This can be
corrected by moving the right shoulder forward a small amount so the rifle
can be moved closer to the correct position. As the picture shows the rifle
butt is out of alignment by about � to 1 inch to the right. Correct this
misalignment if the adjustment has not occurred in prior position
adjustments.
6. Practice dry firing in the new position a few time to get the new feel of
the position.
In looking at the left middle view, we see the rifle pointing low toward the
ground. With the adjustments the rifle will come up into alignment for the
target and the shooting athlete will have a better chance of receiving the
perfect bull's-eye
Hope this helps the shooting athlete to a better position and higher scores.
Chet Skinner, Coach
Entity Sports International
"You have to have a goal, because if you aim at nothing ...You receive nothing."
http://www.geocities.com/colosseum/dome/4512/index.html
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The February '01 edition of Stuff for Sale isn't too far off. If anyone has
anything that they want to have listed, please contact me via return e-mail.
I hope to have the list finalized by mid-February, so let me have your input
(or changes to current listings) by February 11th. Distribution will, as
usual, be via the Washington Smallbore Homepage, via e-mail and very limited
distribution via snail-mail...for the cyber-deprived only.
Shoot 10s!
John Crossman
[email protected]
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ATHLETE QUESTION:
Do we have to get different zeros for the different positions? I have been
just getting the zero while in the prone position and been using that zero
for off hand and kneeling. We do not adjust the rear sight but we do change
the length of the stock and position of the hook.
COACHING RESPONSE:
Your procedure is basically correct.
The key to sighting position is that the cheek is placed upon the same spot
(commonly called spot weld), on the cheek piece of the stock for every
position. Generally, the sights are not adjusted because of position
change. As you related, the stock is lengthened or shortened for
accommodation of the trigger/arm pull length. In addition the cheek piece
is also adjusted in such a manner that will force the head to set upright in
a straight up and down condition and the eye perfectly centered in the rear
sight.
What we find (if correctly adjusted) is no cant of the rifle, and the head
is straight up and down, and lastly the eye is in the dead center of the
rear sight. If you have found the perfect spot on the cheek piece that will
accomplish all the adjustments then repeatedly placing your check upon this
spot then further sight adjustments caused by position change is
unnecessary. Remember that the cheek piece is mounted just under the
cheekbone and about 6 to 8 inches from the rear sight. Make a notch or
something that will tell you by feel that you are on or at the exact spot on
the stock every time. In some cases you will have to remove some of the
wood from the stock but remember that once removed it is gone, never to
return, so be careful of what you do when removing wood from the stock. It
is best that you go to a gunsmith that owns a try-stock and knows how to use
it. Then such adjustments are not trial and error but exact fit to the
stock for every position mounted.
So the key to every shooting position is the correct adjustments of the
stock length and the placement of the cheek piece (commonly called spot
weld) in relation to centering the eye into the rear sight.
So:
1. Adjust the stock length for position and trigger pull length.
2. Adjust the check piece so the eye will be placed in the dead center of
the rear sight.
3. If the first two have been taken care of with precision number three is
not needed...The head will be straight up and down without any cant to the
rifle in any position mounted.
The concept of having to adjust the sights for each position change was
developed as a response (trial and error method) to the head changing
positional alignment during incorrect position mounting sequences.
Chet Skinner, Coach
Entity Sports International
"You have to have a goal, because if you aim at nothing ...You receive nothing."
http://www.geocities.com/colosseum/dome/4512/index.html
[Editor - I have to provide a conflicting point of view to Chet's comments above. Even if you somehow can adjust your rifle so that you do not have to cant the rifle (which as you know I also don't agree with), the resistance the body provides against the rifle in each position cannot be the same so the zero point will not be the same. It may not be much (a few clicks), but it is highly unlikely that the same sight setting will work in all three positions.]
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End of UIT Mailing List #10
Michael Ray - DBA & Systems Engineer
Rose-Hulman Inst. of Tech. Rifle Coach
UIT Shooting Page -
http://www.geocities.com/Colosseum/1190/index.htm
