tube against the retreating
screws to remove all slack
and prevent impact shift
during recoil.
To ensure they hold a
consistent zero Styrka has
designed a heavy duty erector
tube assembly for the full
range, precision- machined
from premium brass which
slides slickly and stronger
springs to make adjustments
repeatable. The clicks can
easily be felt. Accurate,
repeatable adjustments, make
sighting-in a Styrka scope a
fairly straightforward process.
Ground Force International
sent me four sample Styrka
scopes to review, but I could
only test one, and I chose the
S7 2.5- 15x50 with BDC reticle.
In my book this is a simonpure
varmint scope because it has
capped turrets instead of
target turrets and a BDC
second focal plane reticle, not
a first focal plane Mil-Dot
reticle. At 2.5x it could be used
in the bush, while its 15x top
end is about as high as can
feasibly be used under normal
field conditions. And all this
was accomplished while
maintaining eye relief of
400mm throughout the
power range.
Actually, the eye relief of a
varmint scope is not that
critical if it is to be used ontargets that stay put such as
rabbits or perched birds. When
a rifle is to be used from the
prone position, the eye is
naturally farther forward than
it is from the sitting or
kneeling position, and when
it's used from sitting or
kneeling it is naturally closer
to the ocular than it is when
used from the standing
position. Considerable latitude
of eye relief in the Styrka
2.5-15x50 allows the shooter
plenty of time to get his eye in
exactly the right position.
Bigger objective lenses are
needed with high
magnification. When light is
directed through glass, some
of it is lost to reflection. All
things being equal, however, a
scope's brightness is
dependent on the size of its
exit pupil, which is derivedfrom the objective lens
diameter divided by its
magnification. The human eye
is capable if dilating only
5-7mm - so any exit pupil
larger than that is wasted
light. Due to its 50mm
objective, the Styrka has an
exit pupil of only 3.3mm at
15x. That is a usable amount of
light in most conditions, but as
the light fades in late evening
one would benefit by cranking
the power down to 10x to gain
a 5mm exit pupil.
High powered scopes for
varmint shooting like this
Styrka always have some kind
of parallax adjustment so the
users can bring the target in
sharp focus from 50yds to
infinity. Scopes of 8x and
above generally have focusing
objectives or a third turret on
them. Some makers get by
with a 10x focused for a
compromise distance like
150yd, but from 10x on up a
provision for focusing for
various distances is an
absolute necessity.
The Styrka's brightness and
clarity exceeded expectations.
The scope's success in
transmitting light was
especially evident at dawn
and dusk, when, even though
less light is available, the
scope produced clean, crisp
views. Clarity was improved5 4 | SPORTING SHOOTER _ MAY 2018
TEST
REPORTerector tube against these
screws and are tensioned by a
couple of springs. Turning the
screws in and out causes the
tube to move sideways or up
and down. If you turn each
screw to the right, it normally
presses against the erector
tube; when the screws are
backed off, spring tension
moves the tube. Consequently
these adjustments (down and
left on the majority of el
cheapo scopes) are usually
pretty unreliable.
Problems sometimes occur
when we need the rifle's shots
to go up and right because the
springs need to push the
erector tube firmly against
the retreating screw. If the
springs are a little weak, they
don't sit firmly against the
erector tube and the
crosswires may not move or
may jump suddenly after the
dial is turned. Obviously
then, strong springs are
needed to lock the erector
The S7 2.5-
15x50 with
BDC reticle is
in my book a
simonpure
varmint scope.”
4
5
4
St yrka 2.5-15x50mm was
at tached to Winchester Model
70 .270 WSM with medium height
Leupold Q /D rings.
5
Styrka scopes have eyepiece
focusing and power ring has a
thumb ridge.
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