It's what's inside that counts. A few years ago, I was asked to write
an article about the differences in shotshells, in particular
shotshells used for turkey hunting. I elected to entitle that article,
"It's not the Shot, It's the Shell". That article, first published by
"Turkey & Turkey Hunting", is still available on this web site.
When
it comes to choke tubes, it's not really about the exit diameter (many
times incorrectly referred to as constriction) but rather about the
internal geometry.
Many choke tube manufacturers are
justifiably reluctant to discuss the internal geometry of their chokes.
Therefore, some shooters do not have an understanding of this topic or
understand its importance to patterning a shotgun.
The emergence
of "screw-in" extended chokes began with the introduction of the
"Win-Choke" in the late 1960's. It was not immediately well received
but Winchester stayed with the concept, refined it and it was adopted
by other manufacturers as time went on. Those early chokes were pretty
simple and in reality, not much thought was given to the "internals".
The
folks at Briley developed their "straight-rifled" turkey choke after
considering the effect that the internal geometry had on plastic wads
and in turn, the effect that wad had on patterns. By reducing or
eliminating the spin of a wad, the shot cup could hold the shot charge
longer and would positively influence it. The resulting pattern
improved.
The Hastings company recognized the importance of
internal geometry and introduced their Wadlock barrels and chokes. The
idea was the same as Briley's, stabilize the wad and positively
influence the pattern.
Choke tube manufacturers began extending
the chokes used for all types of hunting and shooting sports. With
longer chokes, they could do more internally to influence the shot
string and pattern than with the early short chokes. By changing the
conical section, the parallel section and/or the relationships, they
could do more to influence the pattern than by simply changing the exit
diameter.
It was soon learned by some choke tube manufacturers
that they could tweak the internals, leave the exit diameter the same
and achieve different results.
This learning curve really
advanced with the creation of "heavier-than-lead" loads. The inherently
better patterning characteristics of those pellets, combined with some
innovative shotshells, supported a creative frenzy.
Turkey choke
manufacturers in particular, due in large part to the publicity
afforded by contests such as the "Still Target Shooting World
Championship" created by the National Wild Turkey Federation, really
began to gear up and produce some innovative products.
Some of
the early products produced by Comp N Choke and Kick's, with excellent
internal designs, won World Championships, set records and really
brought positive attention to those products. Each of those chokes has
its own distinctive internal and external features that contribute to
their success.
Choke tube manufacturers employ internal items
such as wad-stoppers, porting of all shapes and sizes, lugs, lines,
grooves and any of a number of other devices to achieve what they
believe to be the perfect pattern.
One challenge that choke tube
manufacturers face is the constantly evolving and changing nature of
the shotshell. The internal geometry of a given choke tube may be
designed to work exceptionally well with a particular shotshell or
group of shotshells from a manufacturer. When the manufacturer changes
that formula, the choke may not work as well and the manufacturer may
have to go back to the drawing board to tweak or perhaps even entirely
change his design.
The old adage about beauty being only skin
deep applies here. The external appearance of a choke tube has little
influence on its performance. Much of what is seen on the outside may
be influenced by market studies or current trends. With choke tubes as
with much else in life, it's really what's inside that counts.