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You are in for a great issue. Several excellent comments and information.
Make sure you read it carefully!
In this issue:
Re: Cheekpiece adjustment (and buttplate)
Re: The problem of canting
Re: The problem of canting
Re: The problem of canting
Re: canting and riser blocks
HW660 firing pin
Anschutz buttplates: 4762 vs 4765
Colored covers for rear iris?
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Many of the recent submissions regarding cant and cheek placement suggest
that some readers would like to know how to adjust a free rifle for both.
There is a simple exercise I use for helping my shooters first find their
correct butt plate (including cant) adjustment and then finding their
correct cheek piece adjustment.
To find the correct buttplate adjustment for a shooter, first remove the
cheekpiece from the rifle. The purpose of this is to ensure that the
shooter keeps their head in a naturally erect position. With the cheekpiece
on, it is possible for the shooter to tilt their head, resting on the
cheekpiece like a pillow. With the cheekpiece off, any tilt of the head
will be felt in the neck muscles. So, with the cheekpiece off the rifle,
make adjustments to the buttplate assembly until the rear sight lines up
directly in front of the eye. What you will find with most shooters is that
the buttplate needs to go a whole lot lower than you thought, and a little
bit of cant adjustment is often needed too. But once you get it correctly
adjusted, the rear sight should line up in front of the eye so well that the
cheekpiece almost seems unnecessary.
However, we of course know that the cheekpiece is very important for
ensuring a consistent head placement, thus ensuring proper sight alignment.
Having found the correct butt adjustment, the cheekpiece adjustment is found
by putting the cheekpiece back on the rifle, and removing the rear sight.
Then, using a target that has a single bull in the center of a very large
sheet of blank paper, the shooter fires shots using only the front sight to
aim. The cheekpiece is adjusted to move the aiming eye, and thus the point
of impact of the shots, until the shots are hitting well inside the bull.
(While doing the exercise, the shooter will often complain that the bull
appears very fuzzy without the rear sight. This is a good opportunity to
demonstrate the merits of using a larger front apperature.) Once the
cheekpiece is adjusted so that the shooter can consistently hit black
without a rear sight, you've found its proper place. Put the rear sight
back on and you're all set. You've got a buttplate adjustment that keeps
the head naturally erect, and a cheekpiece adjustment that guarantees
consistent sight alignment.
A few notes on this exercise. First, the idea of adjusting the cheekpiece
without the rear sight is an old one, certainly not my own. I last heard it
from Frank Briggs when we hired him to coach the Air Force team. Next,
hardware on the rifle may limit your ability to fully exploit this
technique. Older free rifle buttplates only go down so far. To make them
go down far enough for most shooters, you have to do serious modification to
them. The alternative is to add riser blocks under the rear sight instead.
With the post-1984 Anschutz buttplates that have a zillion screws and run up
and down on a center post, you can unscrew the post from the flat plate and
screw it back on a couple of holes lower. This enables you to adjust the
butt elevation correctly for even the longest-necked shooters. A similar
situation exists with the cheekpiece hardware. With the newest Aschutz and
Walther (and I assume FWB) cheekpieces, you should be able to adjust them
laterally enough to get the aiming eye in exactly the right spot. But with
older cheekpieces that only adjust up and down, you may have to either move
the metal plate under the wood to the right or the left (requires a drill
for small adjustments and a Dremel for larger ones) or else sand-down or
beef-up the area where the face makes contact. Since no one really wants to
cut the wood on a $2000 rifle, I'm a big advocate of buying and extra set of
the adjustable cheekpiece hardware ($50) and a 2x4 ($2) and making my own
cheekpieces. One 2x4 allows you to try at least 16 different shapes of
cheekpiece without ever touching your originial stock.
[Editor - Wow! I couldn't have said it better myself.
This is the same thing I do with my shooters. Kudos to Capt. Clark for
actually putting it into words. Some excellent advice here. ]
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Received the UIT list this morning and read the comments on cheek piece and
cant.
Very good and right on Wayne.
The rifle manufactures do leave wood on the stocks so it can be removed
according to the shooters needs and physical structure of the shooter
owner. What most shooters do not understand is that they must fit the stock
to them by rasp work or the band saw as Wayne indicated. The cheek piece
is very important during precise shooting and yet most fail to consider this
fact. When I note Cant, I see shooting athletes who have not taken the
time to size their stocks for the shooting position or eliminate cant. If
this stock fitting action has not occurred then the shooting athlete is not
prepared for the competition they are attempting to enter.
You bought a lovely rifle and stock and the stock is painted with the best
finish money can buy. Good marketing but not for the shooting athlete
because to claim the best that rifle can give and worth the money you spent
in purchasing, is to work or cut the stock so it will fit. Only then
will the shooting athlete achieve rifles total worth and precision during
competition. The shooter can always replace that lovely paint job on the
stock if desired after it is sized to the shooters physical shape.
Don't forget this on cant, You can cant 1 degree or maybe 2 degrees without
effecting the sight adjustments for non-cant sight alignments. The sights
will work just as good and in their normal adjust mode with this small cant.
Thereafter, in a cant situation you will be in double trouble and the
resultant recoil problems.
Fact: when a shooter is canting 1 or 2 degrees, it looks like the shooter is
canting the rifle and therefore this must be good as this is a champion.
This is competition tactics. It is done to trap a less knowledgeable shooter
into making major mistakes. Defense: against this type of competition
tactic is to not be so quick to acknowledge something that appears to be
correct but in fact is wrong and is intended to harm or eliminate the
beginning shooting or a less experienced athlete during competitions.
Any way good show Wayne.
Chet Skinner, Coach
cskinner@dol.net
http://www.geocities.com/colosseum/dome/4512/index.html
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This item was extracted from UIT list #3 number 36. Author unknown.
My comments "///" included in response.
Another aspect to the cant discussion:
The method described by Chet to reach a cant=0 situation talks about
position and forces of the head in relation to the rifle cheek piece.
However, especially for standard / air rifle, shoulder contact is also
involved here.
If you insist on a straight, relaxed head position, you may end up with only
the tip of the butt plat having proper contact with the shoulder. On the
other hand, starting from a good, solid shoulder/upper arm contact, you are
forced to use some (more) rifle cant (and perhaps even head cant) to get eye
and sights aligned.
/// This is true in the case of lessor experienced shooting athletes,
however, the shoulder becomes less important as the caliber if the rifle is
reduced. Shoulder contact with Air rifle is nonexistent and does not
effect the recoil to any great extent. The bigger caliber's increase
there impact upon the shoulder as the caliber's size is increased.
As for the tip of the rifle butt making contact with the shoulder, this
assumption is also correct as the Air rifle does not really need the
shoulder in position. With the rifle positioned across the chest without
touching the chest the rifle butt will be at the upper arm and using the
upper arm in place of the shoulder in position. In the case of Air rifle
the rifle is better if it is allow to move on the recoil axis during recoil.
This means the rifle floats on top of the position with the rifle and head
straight up and down (NO CANT).
In the case of 22SB, the rifle cannot set on the position in the same manner
as the Air rifle but it either must make solid contact with the upper arm or
shoulder at fire time. Have experimented with this off shoulder position
and as long as the SB rifle is all now to move upon the recoil axes to the
rear with out restriction of any kind, the PBE's can be fired as if the
rifle was in the shoulder position. It takes some dryfiring to become
accustomed to the rifle resting high upon the position but it can be done
very easily and with great precision. For those muscle physical shooters
such a thought scares them if they cannot muscle the rifle into the bull and
fire.
Ok, every body don't scream at the same time.......!
Chet Skinner, Coach
cskinner@dol.net
http://www.geocities.com/colosseum/dome/4512/index.html
[Editor - I guess I get to be first to scream. "Shoulder contact with
Air rifle is nonexistent" seems pretty absolute IMHO. Depends upon the
shooter for one and the recoil would be incredibly variable. However, a
bigger issue is what you suggest (the butt resting on the upper arm)
violates the rules. ISSF rule 6.3.2 describes the standing position as
"...The rifle must be held with both hands and the shoulder..."
As for .22, I would love to see a picture of somebody doing what you are
describing. I can't picture in my mind how someone can hold the rifle
further away from their head (out on their arm rather than the shoulder
pocket), not cant the rifle any, and still have any hope of seeing through
the sights.]
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Hello All:
Can I add my two cents worth! Who cares if you cant?!!! Unless
of course you do it inconsistantly and you don't know how to work your
sights for said cant. The empirical side of the house says that many,
many, (sorry Mr. Sagan) shooters can and have used it successfully.
Coaches and good shooters need to apply the reductionist mentality to
troubleshooting in order to learn, but shouldn't forget that the ultimate
goal is to shoot the bullet where you want it to go.
Having said that, I need to get in a few of my own comments. Cant
is necessary to get the shooters aiming eye directly behind the sight with
the least amount of effort. If that can be accomplished without a great
deal of effort then it's great, I'm all for the K.I.S.S. method of
shooting. If it isn't practical (meaning capable of being done without
undue effort) then all the previously mentioned mechanical adjustments
have merit. I would like to mention a couple of other points that I may
have missed or may have not been addressed.
1. Although the effects of gravity are consistant on it's
effect to the projectile, by changing the relationship of the line of
sight to the trajectory of the round, elevation and windage changes are
inevitable. So knowing how to adjust the sights when a cant exists is
very important. So as a reminder, of your early Geometry days or
mechanical drafting classes, the two right triangles that you used to
great effect were the 45 and 30-60. Important for you to know because
when you get to 45 degrees, changes of the sight are 1:1, while the 30-60
degree triangle the ratio to legs were roughly 2:1.
2. In terms of cheek piece adjustment. It's primary
advantage should be in it's ability to give you a comfortable eye height.
That is to say you should be able to sit your face on the stock and
looking straight ahead have the correct elevation of the center of your
eye in a straight line to the rear sight without have to forward tilt or
backing up of the head. The hook and buttplate position will be doing
their primary functions by releiving the amount of neck strain necessary
to shoot the most natural position possible.
3. A dished cheek piece is great for rifles that will be shot
primarily in only one position (i.e. the German style Schutzen rifles),
and the shelf types for a wider range of positions. This is not to say
the dish type comb won't work, but that it is a little more finicky to
adjust. BTW, the cheekpieces that Anschutz supplied with their wood guns
are adjustable laterally, dependant on the model will determine what you
have to do.
4. Many people seem to be forgetting the part of the rifle that
has a major effect on how the rifle will be adjusted for cant. The part
of the buttstock directly opposite the comb and forward of the "toe"
portion of the buttplate if cut out appropriately will allow the shooter
to place the firearm more closely in line with the chest. When that part
of the rifle is not cut and more like an older standard rifle it is
difficult to hold a rifle and not need cant for many barrell chested
shooters as well as require some cant, pitch, hook rotation, length of
pull, and cast as well.
5. Ultimately, it's what works, and keeping things simple are
the guidlines that I try to keep my coaching guidelines by. Define what
you mean by "works" first off, so you have a goal. And then keep it as
simple as possible.
I have to thank Coach Skinner, as he brought about what I've been
looking for in a discussion group. I don't think I've seen so much
worthy discussion in a long time. I'm sure I will be put to task as well,
but I believe, that I have keep on learning if I want to be considered a
professional coach.
And to the editor: Keep up the great work! You have a very
valuable service.
David Lee
Head Coach, Men & Women's rifle teams
University of San Francisco
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I aggree on the projection of the POI being a circle. However, what
factors determine the size of this circle?
In my opinion, the radius of the circle equals the "drop" of the bullet
at the range under consideration. (where "drop" is a ballistic
variable, indicating the height the bullet loses between the moment
it leaves the rifle and the moment it reaches the target). If this is
right, then the blocks do not affect the circle radius, and hence
they do not increase the POI movement due to a given cant error.
Why would the circle's radius equal the drop? Suppose you set
your sights such, that when aimed, the bore points straight at the
centre of the target. Then the POI will be too low by the drop
distance ('D', for short). So how can you make the POI end up in
the '10'? By setting your sights such that the bore points straight
above the '10' on your target, by distance D.
When, from this situation, you rotate around the sight line, the
projection of the bore line on the target describes a circle with
radius = D, and its centre in the '10'. The POI is always at D below
this projection point. Therefore, the POI also describes a circle; its
radius is D and its centre is at D below the '10' (i.e. the top of the
POI circle is in the '10').
Again, if this is true, riser blocks do not increase the effect of cant
error on POI displacement.
For a more detailed description of this line of thought, and some
illustrations, you can have a look at:
http://home-5.worldonline.nl/~jhogema/ballist.htm
Am I right, or is there a flaw in my reasoning... ?
Jeroen Hogema (air rifle, The Netherlands)
jhogema@worldonline.nl
[Editor - Yes, you are correct. Sandy Wilson also wrote to point out my
goof. I didn't fully explain myself I guess. If you added blocks without
rezeroing, you would have a different error displacement since the angles
wouldn't be the same. However, once rezeroed, the blocks would have no
effect since gravity is the only factor involved. I apologize for
misleading anyone - I was already late for work when I put together the
last issue. Oops! I would encourage everyone to read Jeroen's excellent
article on this subject. He has an English version as well.]
******************************************************************
I really enjoy the mailing list and the banter back and forth on canting
and such. There's always something new to learn. I have a question, however,
that you or some of the other subscribers out there may be able help me with.
I've been coaching shooting (B-B Gun) for 18 years and shooting competition
smallbore for the past five years and gradually working my way up in
classifications. I bought a Weihrauch HW660 when I got started and it has
proven to be a great rifle for the price. I'm sure that it's not as fancy as
the Anschutz's out there, but I can't outshoot it yet. I recently broke the
firing pin on the rifle, and have ordered a new one to replace it. What I
can't figure out is what caused it to break in the first place. The pin seems
to be of a somewhat weak design with the round pin extending forward from the
upper edge of the flat firing pin body. This juncture is where it parted. The
juncture is very square and looks to me to be the weakest part of the whole
design. I do quite a bit of dry firing from time to time, always with a spent
shell in the chamber, which I thought would protect the firing pin from
damage. First, what am I doing wrong, if anything? Second, what can I do to
prevent this from happening again? And Third, has anyone else experienced the
same problems with the HW660? I'm really bummed out that I can't shoot until
I get the part from the supplier. I'd appreciate any suggestions.
Larry
[Editor - aside from the possible poor design or quality, make sure you
change your spent shell frequently as the pin may eventually beat it in far
enough to where it is worthless. To prevent it, I would use your already
broken pin to dryfire with unless it was designed in such a way where it
may damage the inside of the bolt doing this.]
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Now a couple questions from your Editor. Is anybody else really
disappointed in the new Anschutz buttplate (4765) that comes on the new
rifles? I find it doesn't offer the full range of adjustments of the older
style (4762) with regards to height and angle of the hook and it is a pain
in the butt to adjust. You have to unscrew the tailhook (the piece on the
very end) screw quite a ways since it uses a pin to hold the angle in 3
possible positions (quite limiting). I'm guessing many people have gotten
rid of that pin as long as the screw will keep it set. The tailpiece
(horizontal part going from the plate to the tailhook) doesn't have any
angle adjustment, just rotational, and I'm finding I have to really tighten
it hard, which concerns me since it is aluminum, to prevent it from moving.
The small pieces meant to conform to your shoulder appear to be worthless
for the most part.
So what am I doing wrong? They charge more money for the new one (probably
because it's machined rather than cast). Seems like a big ripoff to me. I'm
getting ready to buy several buttplates to replace the pre-1984 ones we
have and am thinking I'll stay with the 4762.
******************************************************************
Second question - what are your opinions on the colored covers you can
place on your rear iris? Gehmann claims they "enhance and centrally focus
the eye line and sight picture". Just how does it do this? I can see where
some people may prefer the looks with a green, yellow, silver, red or blue
rear sight face, but would a shooter change it for different light
conditions? I would expect someone to change the *filter* color. Do you
think they would notice a change if they also changed the cover?
******************************************************************
End of UIT Mailing List #37
Michael Ray - Systems Engineer
Rose-Hulman Inst. of Tech. Rifle Coach
UIT Shooting Page - http://www.geocities.com/Colosseum/1190/index.htm