SmartStock
SystemSmartStock
System
(aka) Accurizer
Factory Barrel
Tuning
Richard Kreischer
The last few years have shown a renewed interest in improving accuracy through
tuning barrel harmonics. Many, if not all, of these devices are adjustable
weights, that go on the end of a barrel and by moving the weight back and forth
change the vibration pattern at the end of the barrel. The idea is to minimize
barrel movement as the bullet exits thereby reducing group size. Browning's BOSS
and the 4000 Plus are two examples of the "adjustable weight on the end of
the barrel" type of device that really work.
Over the years I have had several guns, that had innovations intended to change
the vibrational pattern for better accuracy. Some examples that come to mind are
a large bulbous end, on a smallbore rifle barrel turned into the barrel blank.
The additional mass on the end of the barrel caused a choke effect, by reducing
the final diameter of the inside of the barrel. It increased the moment of
inertia thereby increasing time on target besides changing the vibrational
pattern of the barrel. Another device was a way to put pressure on the barrel
through bedding. After bedding the action, place a shim under the action and bed
a small strip under the barrel at the end of the fore-end. When the shim was
removed and the action tightened the bedding, at the fore-end put a positive
pressure on the barrel.
These and other similar devices all improved accuracy to varying degrees. Since
none of these devices are adjustable and vibration changes not only from gun to
gun but with different loads in the same gun the improvements were limited. The
next evolution needed to be an adjustable device. I will say that my experience
indicates that the longer and thinner a barrel the greater the problem. This is
one of the reasons that single shot pistols with short bull barrels like the
XP-100 shoot so well. This is also the reason that the average sporting rifle
can probably benefit the most from the addition of such a device.
Not being sure what rifle to install the Accurizer on, I looked in the
gun locker for a stock sporter. The best I could find was a Remington 700 that
had been modified for silhouette competition. The action was factory stock with
no accuracy mods. The barrel had been replaced with a Douglas Air Gage cut to
24.25 inches and .860 inches at the muzzle. A bull barrel not a slender sporter.
The factory trigger was reworked by Neil Rice to 10 ounces and a Fajen maple
silhouette stock, was installed and bedded in Devcon. I topped that off with one
of Dick Thomas' Premier 30-50x, 50mm scopes. This scope is an absolutely great
piece of equipment and a real pleasure to shoot. It is clear and gathers a lot
of light, a real winner.
The gun was chambered in 7mm TCU, with lose neck clearance. The only loaded ammo
was 100 rounds of Sierra 145 spitzer boat tail, behind 25.0 grains of AA 2460
loaded in 1987. The brass was once fired Lake City military, that had been
resized from .223 but not fireformed. No brass prep had been preformed including
trimming to length. This gun shoots best with match bullets and H322, but this
ammo was ready to go so why not.
Before I get into a description of the actual Accurizer I would like to say that
the thought and effort that went into the development of this device must have
been extensive. The kit is complete. The Installation and Operation Manual is
detailed and contains several good photos. There is not a reason why anyone who
has ever bedded a stock could not install this successfully right out of the
box.
The main components of the kit are an Instruction and Operation Manual, an
Accurizer unit, an Installation Template, an Epoxy Kit, Sandpaper, a
Sling Swivel Screw, and a small Screwdriver. Some additional household tools are
required and a good mold release.
The Accurizer consists of a rectangular aluminum channel 3.5 inches
long and open at the top. Running length wise through the unit is a 6-32 screw
with click adjustments made with a screwdriver. Each click is 1/2 turn of the
screw and causes .0125" movement of the Attenuating Block. The attenuating
block is a cube shaped block of what looks
24 SHOOTER'S NEWS - FEBRUARY 1996
