THE TECHNOID STRINGS YOU ALONG... Shot String. We have all
heard the phrase, but most shooters do not know what it really
means in
terms of pattern performance. Is a long shot string good in that
a bird
can "fly into" it? Does a short shot string put more pellets onto
the
target? Does it matter? Do you care?
Well, of course you care! Shot string is of vital importance if
you are worthy of earning your genuine Junior Technoid plastic
pocket
protector. Shot string is a great subject for a Technoid article
because no
one really understands it, so no one will know when the Technoid
trips
up on the odd little fact or two. E=M/C", E=M+C" or whatever.
Shot string is the flight formation your pellets adopt whilst
wending their way to the target. When you shoot a pattern on a
piece of
paper, you are only getting a two dimensional view of what happened.
All those pellets did not hit that paper like an air-borne pancake.
They
hit it about like a swarm of bees. Some hit first, some came a
little
later. The length of this swarm is the shot string.
Why do pellets string out and not travel together? All the pellets
leave the muzzle at the same velocity, but some of the pellets
are a bit
less round due to being damaged at shell ignition or during the
trip down
the barrel. The pellets at the back of the shot column and along
the sides
of the cup tend to lead the hardest lives. The damaged pellets
are less
aerodynamic and tend to fall back a bit when flying to the target.
The
perfect pellets go through the air more easily and surge ahead.
Some
pellets move forward and backwards in the cloud due to "drafting"
(like
stock cars). The end result is that at 40 yards, your shot cloud
can be
from 6 to 12 feet in length.
Long is not good. Sometimes. On a distant crosser, a very long
shot string will deprive you of a great deal of your effective
pattern.
Take the example of a 40 yard crossing target. The bird is traveling
at
30 mph at the point you are going to shoot it. You are using the
Technoid's recommended 1 1/8 oz 3 dram (1200 fps) load of #7.5s
through your maximo .035" full choke.
Here are the numbers: Your load of #7.5s has slowed down to
675 fps (feet per second) by the time it reaches the target. The
target is
crossing at 30 mph, which is 44 fps. Your effective pattern width
(80%
chance of a two pellet hit defining the fringe) at 40 yards with
maximum
choke and 1 1/8 oz of #7.5s is only about 12". That 30" effective
pattern hype at long yardage is just dreaming. Let's assume that
you
used high quality shot (like Lawrence Magnum with 6% antimony),
so
your shot string at 40 yards is about 6 feet. Hard shot has a
shorter shot
string than soft shot because hard pellets stay round and retain
better
aerodynamics.
It will take 675/6 or .0089 seconds for the entire length of the
6
foot shot string to pass through that 40 yard target. During that
time the
30 mph target itself will have moved across through the pattern
for
.0089*44 = .3911 feet or 4.7 inches. If the part of the pattern
that you
can count on to kill the bird at 40 yards is only 12" wide to
begin with,
you have just given away over 1/3 of that to shot string! The
target will
literally move out of the way before the back third of your shot
string
catches up to it. The two dimensional stationery pattern paper
does not
show this aspect of shell performance.
If you had used a poor quality shell, with easily deformed soft
shot driven at a pellet distorting high velocity, your shot string
could be
as much as 12 feet at 40 yards. This would deprive you of more
than
2/3 of your effective pattern on the above target! This is bad
stuff. The
further away the target is, the more shot string elongates and
the worse
things get.
A long shot string is not always bad. In the sixties the Russian
Olympic skeet team went to great lengths to produce a shell/choke
combination that produced a long shot string at 20 yard skeet
distances.
They reasoned that a long shot string would help them. They would
simply shoot slightly in front of the target and if the front
pellets did not
get the bird, the target would surely run into the following ones.
They
were correct. Why does a long shot string help on short skeet
shots and
hurt on long sporting shots? Long shot string helps in skeet because
of
the very high pellet count of those little #9s. They can afford
to lose
some pattern density due to stringing. They have pellets and pattern
density to burn.
Sporting's long distance crossers are very different. Instead
of
dealing with 651 #9 skeet pellets, you have at most 389 #7.5s
on your
side in a 1 1/8 oz load. At 40 yards a #7.5 has about the same
energy
per pellet as a #9 at 20 yards, so the numbers equate. 389 is
not a high
enough pellet count to give up anything to shot string. Sure,
when you
shoot in front of the bird, the target could still fly into the
trailing shot
string just like the Russian skeet shells. The difference is that
the
skimpy shot string of the #7.5s is not dense enough to insure
the
required two pellet hit because there are not enough #7.5s to
begin with.
Aye, there's the rub. It all comes down to pattern density. Long
shot
strings rob you of density and that means that a bird can sneak
through
your pattern if you do not have a high initial pellet count.
What to do and how to test? Unless you glue a 16 foot piece of
pattern paper to a boat trailer and tow it behind the family car
through a
cow pasture as Bob Brister did, you cannot do much actual testing.
You
can do some sharp surmising though. It is a pretty good guess
that the
shotshells that offer the tightest patterns on your standard stationary
pattern paper, also usually have the shortest shot strings. Bad
or badly
treated shot not only lags behind and strings out, but it also
flies out
laterally to the sides. This will show up as erratic fringe on
your pattern
paper.
You want the roundest hardest shot possible and you want to
launch it as gently as possible and still get the job done. Lower
velocity
shells pattern tighter and have shorter shot strings than high
velocity
cartridges if all other things are kept equal. That is because
more pellets
are deformed under the ignition and setback forces required to
obtain
that high velocity. It stands to reason. Plated shot is better
than
unplated shot, not because the plating adds hardness (it does
not), but
because the plating allows the shot to slip around in the shot
mass as it
moves up the barrel and avoid being crushed as much. It is a lubricity
thing. John Brindle feels that slower burning powders (such as
Green
Dot, one of Don Zutz's favorite powders for tight patterning shells)
also
distort shot a little less by providing a somewhat smoother initial
launch.
Choke does not really seem to affect shot string at long distance.
Full choke does not "string 'em out" any more than cylinder bore
shoots
a pancake. Some semi-wise pundits disagree, basing their opinions
on
old shot string photography taken at the muzzle or a few feet
beyond.
At those close distances, full choke does indeed string out more
than
cylinder bore. More modern photographic techniques capable of
showing the string at 30 yards, prove that the pellets resort
themselves
based on aerodynamics, not choke. With the same shell, full and
cylinder produce about the same string length at distance. Full
choke
may distort pellets a tiny bit more due to squeezing in the choke,
but it
mostly really depends on initial pellet quality and launch setback
Trap shooters have known all this for years. A 27 yard handicap
shooter is hitting his birds at well over 40 yards. True, they
are not
crossers and thus less susceptible to shotstring loss, but shell
performance is still paramount at that distance. For long range
sporting
clays shots, you never go wrong buying a premium handicap trap
shell.
Anything less is just cutting down your percentage chances of
a hit.
Most Travelers' courses usually have a station or two of long
ones.
Make sure that you have a box of super premium #7.5s lurking in
your
shoot kit. It will be worth your trouble.
So there it is. The long and the short of shot string. Another
dose of salts from your nearly dearly beloved Mephisto of Myriad
Mystical Mechanical Marvels. Sheath that slide rule!