Guns 2012-08.pdf - Jeffersonian

arrangement. They have two other
reticle configurations with this same
sort of functionality.
The Bushnell Elite 3.5-21x50mm
Tactical scope proved to be an
excellent example of good optical
design. Curvature of field was very
minimal. I could detect no barrel or
pincushion distortion, or any rolling
distortion at any power from 3.5-21X,
which by the way is a 6X factor range.
Only a few years ago, a 4X factor
range was about all the manufacturers
could coax out a design. Now we are
seeing power ranges of 10.
Resolution and contrast were
excellent. The scope was clear with
no color fringing. There was no
detectable astigmatism at any power.
In a short length, large objective,
“fast” optical system, high index
glasses are utilized to minimize the
radius requirements that assist in
controlling optical aberration. High
index glasses tend to separate the
wavelengths more than low index
glasses do, making correction of
this separation more challenging.
Because of this, these glass types
and radii, especially in the objective
lenses, combine to generate a residual
secondary spectrum.
This is often prevalent with large
objective, “fast” optical systems.
Secondary spectrum is often dominant
near the edge of the exit pupil.
However, it should also be viewable
while looking at a high contrast
“white and black” target when moving
your head away from and toward the
exit pupil along the axis of the scope.
In this case the center of the field of
view will tint towards the yellows on
the inboard side and towards blue on
the outboard side of the exit pupil.
Movement side to side in the exit
pupil behaves similarly for viewing
secondary spectrum. With head
motion to the left, typically the edges
of a high contrast target tints towards
the blue near the center of the field of
view and yellow away from the center
of the field of view.
The Bushnell scope displayed this
phenomenon. However, it is a problem
with almost any scope in this class. I
had another very expensive tactical
DMR 3.5-21x50mm –
Mil-Dot
Maker: Bushnell
9200 Cody
Overland Park, KS 66214
(800) 423-3537
www.gunsmagazine.com/bushnell
Magnification: 3.5X – 21X, Objective Diameter:
50mm, Tube Diameter: 34mm , Click Value: .1 mil
(tested), 1/4 MOA, Overall Length: 13.2", Reticle:
Mil-Dot, Price: $1,499.99
The scope is returned to zero after sighting in
by removing the top of the turret (above). A coin
or screwdriver is used to remove it. To change
range settings on the scope, one has to lift the
turret and turn. Once the setting is changed,
push back down to lock it. Here you can also
note the position of the Trijicon red dot on
the GDI mount. Shown is the underside of the
GDI mount and the locking handles (below). It
indexes in the Picatinny rail via the small raised
area in the middle of the mount’s bottom. Closing
the handles secures the mount to the rail.
scope with me during the tests, and
it displayed the same tinting when
moving the head from side to side
and up and down. However, when the
head is in the proper position, no such
tinting can be seen.
Besides the new DMR 3.5-21x50
and the CQB 1-6x24mm, Bushnell
offers a 2.5-16x42mm, a 3-12x44mm,
a 5-15x40mm, a 6-24x50mm, and a
4.5-30x50mm, each with different
reticle configurations. If you can’t
find what you want from that lineup,
I would be very surprised.
LaRue Tactical
850 County Rd. 177
Leander, TX 78641
(512) 259-1585
www.gunsmagazine.com/larue-tactical
Global Defense Initiatives, Inc.
33175 Temecula Pkwy., Ste. A-637
Temecula, CA 92592
Fax: (951) 303-0985
www.gunsmagazine.com/global-defense
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WWW.GUNSMAGAZINE.COM • AUGUST 2012