Choke and its effectiveness
are very much affected by your choice of cartridge. In fact, when
choke was first used in shotguns, it actually resulted in worse
patterns. Lead is a very soft metal quite prone to deformity. As
the shot travels down the barrel at great speed and high pressure,
it is inevitable that there will be some damage to its round shape.
The degree of this damage relates directly to pattern quality. The
more deformity, the poorer the pattern.
Much of this shot damage was prevented by the introduction of antimony
into lead shot to increase its hardness. In addition to shot hardness,
other components of the shotshell also affect its patterning performance.
The modern shotshell cartridge is, in effect, like the plunger or
piston in a bicycle pump. The primer being struck ignites the powder
that, combined with the case and crimp, creates sufficient pressure
to propel the shot charge along and out the barrel. The wad must
be capable of protecting the shot charge from the heat of powder
combustion as well as barrel contact while at the same time acting
as a piston and seal to make best use of the pressure generated.
The shot must be of sufficient hardness to resist deforming while
being driven down the barrel.
Wads are either felt, fiber, or plastic, the first two often being
chosen for environmental reasons. There can be no argument that
the plastic wad is superior, its shot cup protecting the pellets
on their journey down the barrel.
The main shot sizes used for clays include No.
9s, 8s, and 7 1/2s. The larger the number the smaller the diameter
of individual pellets--and the less energy per pellet. If you shoot
7/25, you have bigger shot and more striking power but fewer pellets
than in an equivalent load of 8s. A simple rule of thumb is, out
to 35 yards, stick to 8s; past that, 7 1/2s are best. Some shooters
favor smaller 9s for wider, more dense patterns at really close
In recent articles, we have mentioned
recoil, and the shotshell, aside from the weight of the gun, is
a big factor in recoil control. You should take this into consideration
when making your personal choice of shell. Excessive recoil is both
fatigue inducing and the cause of many second-barrel misses.
Speed And Lead
The difference in lead required
for a 40-yard target between the average and the fastest cartridge
is but a few inches. Surely it is better to find a favorite cartridge
and stick with it than continually experimenting with the rocket
science of velocity's small effect on lead.