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Viper® riflescopes are rugged performers built for strength and durability
with a single-piece tube of aircraft-grade aluminum. Premium, fully
multi-coated optics deliver the detail and color differentiation needed for
hunting in any environment. Engineered and designed to perform where
comparable scopes fall short, the Viper delivers. No questions asked.
Please read entire manual before using your new optic.
The Focal Plane
All riflescope reticles can be termed either first focal plane (FFP)
or second focal plane (SFP) according to the internal location of
the reticle within the scope. This model features a second focal
plane reticle design.
Second Focal Plane Reticles
Second focal plane reticles are located near the eyepiece behind
the image erecting and magnifying lenses. This style of reticle does
not visually change in size when you change the magnification.
The advantage of an SFP reticle is that it always maintains the
same ideal visual appearance.
Your Viper riflescope uses a fast focus eyepiece designed to quickly and
easily adjust the focus on the riflescope’s reticle.
To adjust the reticle focus:
1. Look through the scope at a blank
white wall or up at the sky.
2. Turn the eyepiece focus knob in or
out until the reticle image is as crisp
TIP: Try to make this particular
adjustment quickly as your eye will try
to compensate for an out-of-focus reticle.
Once this adjustment is complete, it will not be necessary to re-focus
every time you use the crossbow scope. However, because your eyesight
may change over time, you should re-check this adjustment periodically.
Looking directly at the sun through a crossbow scope, or any optical
instrument, can cause severe and permanent damage to your eyesight.
Windage and Elevation Adjustments
Your Viper riflescope features adjustable elevation and windage
turret dials with audible clicks. Each audible click moves the bullet’s
point-of-impact 1/4 of a minute of angle (MOA). 1/4 MOA closely
corresponds to 1/16 inch at 25 yards, 1/8 inch at 50 yards, 1/4 inch at
100 yards, and 1/2 inch at 200 yards.
It will take four (4) clicks to move the bullet’s point-of-impact
approximately one inch at 100 yards.
To make turret adjustments:
1. Remove the outer turret covers.
2. Turn the turret in the appropriate
direction: up/down or left/right as
indicated by the arrows.
3. Following the directional arrows, turn
the dials in the direction you wish the
bullet’s point-of-impact to go to.
TIP: After sight-in, you can re-align the zero marks on the turret
dials with the reference dots if you wish (see Indexing Adjustment Dials
with Zero Reset on page 12). Replace the outer covers when done.
Using the Side Focus
Parallax is a phenomenon that results when the target image does not
quite fall on the same optical plane as the reticle within the scope.
When the shooter’s eye is not precisely centered in the eyepiece, there
can be apparent movement of the target in relation to the reticle,
which can cause a small shift in the point of aim. Parallax error is most
problematic for precision shooters using high magnification.
Select Viper riflescopes (PA models) feature a side focus dial to adjust
for maximum image sharpness and eliminate parallax error. Models
without the side focus adjustment and are factory-focused at a distance
of 100 yards.
Setting the side focus:
1. Be sure the reticle is correctly focused
(see Reticle Focus on page 5).
2. Turn the side focus adjustment
dial until the target image is as sharp
as possible. The yardage numbers
referenced on the dial should closely
match the actual yardage to the target.
3. Check for parallax error by moving your head back and forth
while looking through the scope. The focus is correct if there is no
apparent shift of the reticle on the target. If you notice any shift,
adjust the focus knob slightly until all shift is eliminated.
To get the best performance from your Viper riflescope, proper
mounting is essential. Although not difficult, the correct steps must
be followed. If you are unsure of your abilities, it would be best to use
the services of a qualified gunsmith.
Rings and Bases
Viper riflescopes are available with either a 30 mm or 1-inch tube so
select the ring size that matches the tube diameter of your riflescope. Be
sure to select a base and matching rings appropriate for your rifle and
mount according to the manufacturer’s instructions.
Note: Vortex Optics recommends not exceeding 18 in/lbs (inch/pounds)
of torque on the ring screws.
TIP: Select the lowest ring height that will provide complete clearance
between the riflescope and rifle in order to avoid contact with barrel,
receiver, bolt handle or any other part of the rifle. A low mounting
height will help assure proper cheek weld, aid in establishing a solid
shooting position, and promote fast target acquisition.
Eye Relief and Reticle Alignment
After installing the bottom ring halves on the mounting base, place
the riflescope on the bottom ring halves and loosely install the
upper ring halves. Before tightening the scope ring screws, adjust for
maximum eye relief to avoid injury from recoil:
1. Set the riflescope to the middle of its magnification range.
2. Slide the riflescope as far forward as possible in the rings.
3. While viewing through the riflescope in a normal shooting
position, slowly slide the riflescope back towards your face. Pay
attention to the field of view. Stop sliding the riflescope back as
soon as you see the full field of view.
4. Without disturbing the front-back placement, rotate the
riflescope until the vertical crosshair exactly matches the vertical
axis of the rifle. Use of a reticle leveling tool, a weight hung on
a rope, flat feeler gauges, or a bubble level will help with this
Note: After aligning the reticle, tighten and torque the ring screws
down. Vortex Optics recommends a torque setting of 15-18 in/lbs on
the ring screws.
Initial bore sighting of the rifle and scope will save you money and
time at the range. This initial sighting can be done in a number
of ways. You may want to use a mechanical or laser bore sighter
according to the manufacturer’s instructions. On some rifles, bore
sighting can be done visually by removing the bolt and sighting
through the barrel.
To visually bore sight a rifle:
1. Place the rifle solidly on a rest and remove the bolt.
2. Sight through the bore at a target approximately 100 yards away.
3. Move the rifle and rest until the target is visually centered inside
4. With the target centered in the bore, make windage and
elevation adjustments until the reticle crosshair is also centered
over the target.
Final Range Sight-In
After you have bore sighted your rifle and scope, you should go to
the range and do a final sight-in using the exact ammunition you
expect to use while shooting. Sight in and zero your riflescope at
the preferred distance. 100 yards is the most common zero distance,
although a 200-yard zero may be preferred for long range applications.
1. Be sure the reticle is in focus (see Reticle Focus on page 5) and
set the side focus adjustment (if present) to match the distance
being used for sight-in.
2. Following all safe shooting practices, fire a three-shot group as
precisely as possible.
3. If the shot group is not centered on the bullseye, adjust the
point-of-aim using the windage and elevation turrets (see Windage
and Elevation Adjustment on page 6).
TIP: If the rifle is very solidly mounted and cannot be moved,
simply look through the scope and adjust the reticle until it is
centered on the fired group.
4. Carefully fire another three-shot group and see if the bullet
group is centered on the bullseye. If the bullet group is not
centered, repeat Step 3.
This procedure can be repeated as many times as necessary to achieve
a perfect zero.
Indexing Adjustment Dials with Zero Reset
Viper riflescopes feature windage and elevation dials that allow you
to re-index the zero indicator after sight-in without disturbing your
settings. Though not a required process, resetting the windage and
elevation dials allows you to quickly return to your original zero if
temporary corrections are dialed in the field.
Reset the windage and elevation dials in this way:
1. Remove the outer cap.
2. Pull the adjustment dial outward against the spring tension until
3. With the dial pulled fully outwards,
rotate the dial to align the “0” with
the etched indicator line on the scope.
4. Release the dial, allowing it to
return to the normal inward position.
5. Replace the turret cap.
The fully waterproof and fogproof Viper riflescope requires very
little routine maintenance other than periodically cleaning the
exterior lenses. The exterior of the scope may be cleaned by wiping
with a soft, dry cloth.
When cleaning the lenses, be sure to use products that are
specifically designed for use on coated optical lenses such as the
Vortex Fog Free cleaning products or LensPen.
• Be sure to blow away any dust or grit on the lenses prior to
wiping the surfaces.
• Use your breath, or a very small amount of water, to remove
dried water spots. Isopropyl alcohol can help remove marks like
All components of the Viper riflescope are permanently lubricated,
so no additional lubricant should be applied.
Note: Other than removing the turret caps, do not attempt to
disassemble any components of the scope. Disassembling the scope
may void the warranty.
If possible, avoid storing your scope in direct sunlight or any very
hot location for long periods of time.
Many times, problems thought to be with the scope are actually mount
problems. Be sure that the correct base and rings are being used and
are in the correct orientation. Be sure that the base screws and rings are
tight. An insufficient windage or elevation adjustment range may indicate
problems with the rings, base, base alignment, base mount holes drilled in
the rifle’s receiver, or barrel/receiver alignment.
Check for Correct Base and Ring Alignment
1. Roughly center the reticle by adjusting both windage and elevation
turrets to the mid point of their travel ranges.
2. Attach the bore sighter, or remove bolt and visually bore sight the
3. Look through the scope. If the reticle appears way off center on the
boresighter image or when compared to the visually centered target
when looking through rifle’s bore, there may be a problem with the
bases or rings being used. Confirm that correct base and rings are being
used—and in the proper orientation.
Tips for Solving Bullet Grouping Problems
• Maintain a good shooting technique and use a solid rest.
• Check that all screws on rifle’s action are properly tightened.
• Be sure rifle barrel and action are clean and free of excessive oil or
• Check that rings are correctly torqued per the manufacturer’s
• Some rifles and ammunition don’t work well together—try
different ammunition and see if accuracy improves.
The VIP Warranty
We build optics based on our commitment to your absolute satisfaction.
That’s why Vortex products are unconditionally guaranteed and we
make this Very Important Promise to you—a Very Important Person.
Rest assured that in the event your Viper becomes damaged or
defective, Vortex Optics will repair or replace the riflescope at no
charge to you. If we cannot repair your riflescope, we will replace
it with a riflescope in perfect working order and in equal or better
physical condition. Call Vortex Optics at 800-426-0048 for prompt,
professional, and friendly service.
2120 West Greenview Drive
Middleton, WI 53562
Note: The VIP warranty does not cover loss, theft or deliberate damage
to the product.
is part of the Marketing team at Optics Trade. She is a nature and astronomy enthusiast, that’s why you’ll find most of her articles in these two categories.