March/April 2009 - New Zealand Clay Target Association

gun-smith take a look before you make
changes. Have one of the top custom
shops do this type of work.
Industry standards are not available,
but most agree a 2_ -degree cone is
best for two reasons: It will be 3” – 4”
long, depending on bore size, and wall
thickness won’t be compromised. The
cone should always be highly polished
and, when viewed from the breech,
should not have a shadow over the
length.
Porting, which helps reduce muzzle
jump, is the second most popular
aftermarket alteration. The design
and method are the most important
factors to pay attention to here. All
porting should be done with plunge
EDM (Electro Discharge Machining) for
a burr-free bore and should have the
highest possible position on the barrel
for maximum downward thrust.
The shape of the porting holes is not
important. Just check at your gun
club to see what shape is popular.
Ask if it is clean, loud, etc. One
minor misconception about porting
is it does not actually make guns
louder. It merely allows the sound
and shock-waves to escape to the side
of the gun. Since that’s likely where
you’re standing as the shot happens, it
may sound louder. You’ll find there are
favourite shops around the country to
do this type of work. Ask at the club
for recommendations.
Backboring
Backboring is another popular method
of creating “nirvana” in the shotgun
world; however, it’s not the cure for all
things amiss. New models have larger
bores from the factory and, with Italian
proof law getting more encompassing,
thanks to Beretta, the common bore
size today is .730-.735 for 12-gauge
shotguns. Almost all formerly custom
benefits are built in now.
What does it mean to you if your bore
is smaller? While there is no proof a
backbored barrel kicks less than, say, a
shotgun with a .725 bore, the industry
graph shows the peak of recoil is
spread over a longer period of time
with a backbored barrel, thus, “felt”
recoil is reduced. My old friend, the
late, great Bob Brister, would say the
larger bore sizes allow the pellets in a
load to “find themselves.” He believed
this brief time of “self-awareness” is
perceived by the shooter as softer
recoil. Knowing that, I would always
combine long forcing cones with a
backbored barrel for maximum gain.
If you consider backboring, remember
two things. Your choke or chokes will
need to be remade to reflect the new
bore size. For example, your original
bore size of .725 with a choke of .010
(Improved Cylinder) if bored to, say,
.735, will add an additional .010 to
that choke. Now that choke is actually
a Modified in the same barrel. Also,
the seat of any screw-in choke cannot
interfere with or be smaller than
the bore or you will lose the choke
down-range, with terrible residual
damage to your barrel (trust me on this
one).
Backboring should only be performed
by supreme members of the trade who
understand how honing works. Also,
don’t forget backboring will reduce
the weight of the barrel, which can
be a good thing; however, if recoil is
your problem, you may be helping that
hard-kicking shotgun get even more
vicious.
More Changes
At this point, you should be very close
to your idea of perfection. There are
many aftermarket items that can be
installed yourself, especially if you
own a Browning, Remington or Beretta
autoloader. Take some time at the
range to look at what additional things
are done by other shooters, then ring
up the custom shops and ask. They
will help you decide what might be
most beneficial to you.
One more item to consider purchasing
for improved performance is an
aftermarket screw-in choke. The
simplest and easiest way to add weight,
lose weight, extend barrel length
or improve the performance of our
fowling piece has to be the numerous
makers of aftermarket chokes. They
offer ported models, colour-coding,
specialty materials and hunting chokes.
Who’s best is not the issue, as they all
have a niche in the market. Decide
what you want or need and then pick
a company that offers unconditional
service and satisfaction.
I personally use unported chokes
because I could never perceive the
value of unidirectional ports. A shot
column is being pushed rather slowly,
and the idea of wad retention from a
series of holes is just not plausible to
me. Besides, on my gun they were
always really dirty. I don’t know why
someone didn’t clean them!
I’ve had more than a few years of
experience performing this sort of
work on shotguns, so I hope my advice
sheds some light on what’s available
and may be useful to you. Don’t settle
for a gun that isn’t made for you. Good
luck and good shooting!
A native Texan, Chuck Webb operated
a gunsmithing shop in 1980, blending
his lifelong passion for understanding
how things work and talent for
woodcarving and painting.
Article by Shotgun Sports
Gunshot 37