Vortex Optics VIPER XBR 2.5-10X44 CROSSBOW SCOPE User Manual

The VorTex® Viper® xBr™ CrossBow sCope

The Vortex®Viper®XBR™ crossbow scope is intended for extended
range crossbow shooting. With the XBR, you have the unique ability
to choose between using the elevation turret or the reticle when
compensating for arrow drop on long shots.

Dual Use: Shooting Tactical / Hunting

US P a t e n t 7,9 37, 8 7 9

Fast Focus Eyepiece

Reticle Focus

Magnification
Adjustment Ring

Illumination
Adjustment Dial

MagView

Winda ge
Adjustment Dial

Elevation
Adjustment Dial

Objective
Lens

— Please read entire manual before using your new optic.

3 2

reTiCle opTions

The Focal Plane

All scope 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.

Important Note: The marked Viper XBR 2.5-10x44 crossbow scope
reticle subtensions used for arrow drop and wind drift compensation
are correct at a magnification of 10x.

CrossBow sCope AdjusTmenTs

Reticle Focus

The Viper XBR crossbow scope features a fast focus eyepiece designed to
quickly and easily adjust the reticle focus.

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 as possible.

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.

Warning

Looking directly at the sun through a crossbow scope, or any optical
instrument, can cause severe and permanent damage to your eyesight.

Adjust the Reticle Focus

5 4

Windage and Elevation Adjustments

The Viper XBR scope features precision finger-adjustable elevation and
windage dials with audible clicks.

To make adjustments:

1. Following the directional pointer
on the turret cap, turn the dial in
the direction you wish the arrow’s
point-of-impact to go: up or down, left
or right.

2. Replace the outer cover on the
windage turret when done.

TIP: After sight-in, you can re-align
the zero marks on the windage turret
dial with the reference dots if you wish (see Indexing the Windage Dial with
Zero Reset on page 18).

Elevation Dial

Windage Dial

MOA Adjustments

The Viper XBR crossbow scope uses finger adjustable elevation and
windage turrets with scales measured in minutes of angle (MOA).
MOAs are a unit of angular measurement which approximately
equals one inch at 100 yards.

• The tactical-style elevation turret design provides a high
travel range along with rapid adjustment ability. Each click of the
elevation turret will provide

1 MOA of reticle movement.

• The windage turret features a standard design with an external
cap. Each click of the windage turret will provide

1 MOA of

reticle movement.

MOA at Common Distances

Remember that one click of the turret equals 1 MOA .

1 MOA =

1 inch at 100 yard s

1/2 inch at 50 y ard s

1/3 inch at 33 y ard s

1/4 inch at 25 ya rds

1/5 in ch at 20 yard s

7 6

Turret Rotation

Vortex’s patented Radius Bar visually assists keeping track of turret
rotations and provides a quick visual reference that allows you to
confirm:

Radius Bar

• Dial orientation is correct and has
not shifted as a result of accidental
contact.

• Dial orientation is at the zero point
when using the CRS feature (see page

10).

TIP: By watching the position of the
bar while making elevation adjustments,
you are able to quickly track full, half, and quarter rotations.

To get these benefits from the Radius Bar, the “0” mark on the turret
must be indexed with the zero reference line on turret post (see
Setting the CRS Stop and Indexing Elevation Knob on page 17).

Variable Power Adjustments

To change the magnification, turn the magnification ring to the desired
level. The MagView fiber optic magnification indicator provides a low
light reference for magnification level. A small tactile indent at the 5x
magnification setting allows you to quickly select 5x.

Illumination Adjustments

The Viper XBR scope features

Batter y Cap

a reticle illumination system
with variable levels of intensity
to aid in low light performance.

To activate the illumination,
rotate the adjustment dial
in either direction. This

Illumination
Adjustment
Dial

illumination dial allows for 10
levels of brightness intensity; an off click between each level allows you
to turn the illumination off and return to a favored intensity level with
just one click.

Replacing the Battery

1. Unscrew the outer cap with a coin.

2. Remove the battery.

3. Replace with a new CR 2032 battery.

4. Re-install the outer battery cap and be sure to fully tighten it.

Magnification
Adjustment

Ring

MagView

Indicator

9 8

Customizable Rotational Stop (CRS)

The elevation turret on the Viper XBR crossbow scope features the
unique CRS rotation stop. After sighting in the crossbow, the CRS
allows you to quickly and easily return to an original zero point
after dialing in arrow drop corrections.

The CRS feature is particularly useful when dialing large multi­revolution elevation corrections. The CRS allows you to quickly
spin the elevation dial back to the original zero without having to
carefully count revolutions or clicks.

See how to install CRS shims in the Setting the CRS Stop and
Indexing Elevation Dial section on pages 17–18.

CRS Shims

Focus and Parallax

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 your 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.

The Viper XBR crossbow scope is factory-focused at 75 yards and will
have minimal parallax at distances from 35 to 125 yards. At distances
closer than 30 yards, there may be a very slight shift of the reticle on
the target (parallax) if your eye is not centered directly behind the
scope’s eyepiece. This shift can be eliminated by keeping your eye
centered behind the scope when shooting.

11 10

CrossBow sCope mounTing

The XBR scope requires 30 mm mounting rings of a medium or high
height. Most modern crossbows have a pre-installed Weaver base, so
your ring choice should be compatible with this type of base.

Due to the typically short stock used on crossbows, Vortex Optics
highly recommends using at least one cantilever or extension ring in
combination with a standard ring when mounting your scope. This
combination allows the scope to be placed in a more forward position
than possible when only using standard rings and provides the
optimal sight picture. Be sure the rings are identical in height.

TIP: For specific ring recommendations, please refer to the Viper
XBR product page at www.vortexoptics.com.

Eye Relief and Reticle Alignment

Install the bottom ring halves on the mounting base. Place the
crossbow scope on the bottom ring halves and loosely install the
upper ring halves. Before tightening the scope ring screws, adjust for
comfortable eye relief:

1. Set the scope to the middle of its magnification range.

2. Slide the scope as far forward in the rings as possible.

3. Look through the scope while in your normal shooting position
and slowly slide the scope towards your eye. Stop sliding the scope
when you see the full field of view.

4. Without disturbing the front-back placement, rotate the scope
until there is an exact match between the vertical crosshair of the
reticle and the vertical axis of the crossbow. Use a reticle leveling
tool, a weight hung on a rope, flat feeler gauges, or a bubble level to
help with this procedure.

After aligning the reticle, tighten and torque the ring screws down
per the manufacturer’s instructions. As a general rule, Vortex Optics
recommends torquing the ring screws to 16 in/lbs.

Due to typically short stocks used on crossbows, Vortex highly
recommends using a cantilever ring with the Viper XBR scope.

Use bubble levels to square the
crossbow scope to the base.
Shown on a Scorpyd reverse
draw crossbow.

13 12

sighTing in The xBr CrossBow sCope

For the best long-range ability, Vortex recommends a 30-yard zero on the
center crosshair. Begin the initial sight-in at a distance of 8 yards. Due to arrow
trajectory, this will also closely equal the desired 30-yard zero. Points of impact
between 8 and 30 yards will be just slightly high and may be compensated for
by holding point of aim on the first reticle tick above center. Once you have
mounted your XBR scope, use either the reticle or ruler method to sight in your
scope.

Sight In Method Using the Reticle

Step 1

While looking through the scope, use the reticle hashmarks to measure the
distance the arrow missed the bullseye. Set the magnification to 2.5x then
aim and shoot for the bullseye at a distance of 8 yards. Try to keep your
eye centered behind the eyepiece in order to reduce the effects of parallax
at this very close range. Most likely, you will not hit the bullseye with this
initial shot. Important Note: Hashmarks as seen in the reticle are marked in
increments of 5 MOA, but at 2.5x these increments actually span 20 MOA.

Example

When looking through the scope, the arrow
strike is 1 hashmark high and 2 hashmarks to
the right of center.

1. Calculate amount of adjustment needed:
Elevation: 1 x 20 MOA = 20 MOA
Windage: 2 x 20 MOA= 40 MOA

2. Adjust the turrets (each click equals 1
MOA):
Elevation: Rotate turret down 20 clicks.
Windage: Rotate turret left 40 clicks.

3. Shoot another arrow to check adjustment. Repeat as necessary.

Step 2

Due to trajectory arc, the initial 8-yard zero will closely correspond to the
desired final 30-yard zero. Move the target back to 30 yards, adjust the scope
to a magnification of 5x and shoot another arrow at the bullseye. Be sure to
keep your eye centered behind the eyepiece.

Example

Looking through the scope, the arrow strike is 1 hashmark low and 1.5
hashmarks left of the bullseye. Important Note: Hashmarks as seen in the
reticle are marked in increments of 5 MOA, but at 5x these increments will
span 10 MOA.

1. Calculate amount of adjustment needed:
Elevation: 1 x 10 = 10 MOA
Windage: 1.5 x 10= 15 MOA

2. Adjust the turrets (each click equals 1
MOA):
Elevation: Rotate the turret up 10 clicks.
Windage: Rotate the turret right 15 clicks.

3. Shoot another arrow to check adjustment. Repeat as necessary.

Sight In Method Using a Ruler

Step 1

Use an inch-based ruler to measure the distance your arrow misses the
bullseye. Set the magnification to 2.5x, then aim and shoot from a distance of
8 yards. Try to keep your eye centered behind the eyepiece in order to reduce
the effects of parallax at this very close range.

1. Measure the distance your arrow missed the bullseye in inches. Divide
your measurement by .08 to convert to MOAs. At 8 yards, one MOA equals
.08 inches and each turret click adjusts the point-of-impact .08 inches.

2. Rotate the turret to move the appropriate number of MOAs in the
direction you wish the arrow’s point-of-impact to move.

15 14

Example

The arrow strike is 2 inches high and 4 inches to
the right of center.

1. Calculate amount of adjustment needed:
Elevation: 2 ÷ .08 = 25 MOA
Windage: 4 ÷ .08 = 50 MOA

2. Adjust the turrets (each click equals 1 MOA):
Elevation: Rotate the turret down 25 clicks.
Windage: Rotate the turret left 50 clicks.

3. Shoot another arrow to check adjustment and repeat as necessary.

Step 2

Due to trajectory arc, the initial 8-yard zero will closely correspond to the
desired final 30-yard zero. Move the target back to 30 yards, adjust the scope
to a magnification of 5x and shoot an arrow at the target center. Be sure to
keep your eye centered behind the eyepiece.

Example

Measuring on the target, the arrow strike is 1.2 inches low and 1.8 inches left
of center. Important Note: One MOA will equal .3
inches at 30 yards.

1. Calculate amount of adjustment needed:
Elevation: 1.2 ÷ .3 = 4 MOA
Windage: 1.8 ÷ .3 = 6 MOA

2. Adjust the turrets (each click equals 1 MOA):
Elevation: Rotate the turret up 4 clicks.
Windage: Rotate the turret right 6 clicks.

3. Shoot another arrow to check adjustment and repeat as necessary.

Setting the CRS Stop and Indexing Elevation Dial

After obtaining a satisfactory zero, the CRS stop can be set using the
following technique:

1. Loosen the three turret cap retaining screws on the elevation turret
and gently pull the turret cap straight up and off of the turret post. Be
careful not to rotate the turret post.

2. Slide the CRS shims on the center
section of the turret post below the
V-grooved part.

3. Alternate the shim installation direction
180 degrees with each shim. Use only as
many shims as necessary to completely fill
the space. If a shim does not fit, do not
force it in place.

Once the clearance is tight, do not try to force in another shim.

4. After filling the center gap on the post with shims, replace the
elevation cap.

5. Align the turret cap so the “0” mark on the cap lines up with the
“0” reference line on the turret post. Don’t rotate the actual turret
mechanism in the process.

6. Tighten the retaining screws, but do not overtighten. Use of thumb
and forefinger on the short end of the hex wrench will provide sufficient
force.

17 16

Place the CRS
shims in this
groove.

Using the CRS Zero Stop

Now that you have installed the CRS shims, you can rotate the elevation
dial clockwise and easily return to the original zero point after making a
temporary elevation adjustment. The dial will stop turning just past the
original zero.

Turn clockwise until the
turret stops.

Now, turn the elevation dial counter-clockwise until the Radius Bar is
aligned so the scope axis and zero mark match. This setting will match
the original zero point.

Turn counter-clockwise
until the Radius Bar aligns
with the zero mark on the
scope body.

TIP: If re-zeroing at a future time, be sure to remove all CRS shims
before sight-in.

Indexing the Windage Dial with Zero Reset

The Viper XBR scope features a windage dial that will allow you
to re-index the zero indicator after sight-in without disturbing your
settings. This allows you to quickly return to your original zero if
temporary windage corrections are used in the field.

Index the windage dial as follows:

1. Remove the outer cap.

2. Pull the adjustment dial
outward against the spring
tension until it stops.

3. With the dial pulled fully
out, 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 windage turret
cap.

Pull dial outward to adjust.

Align the “0” with the etched
indicator line on scope.

19 18

how To shooT AT long rAnge wiTh The xBr

Think of arrow drop in MOAs, not inches.

The first step to successful long range crossbow shooting using the XBR
is to learn to think of arrow drops in MOAs (not inches). This has the
tremendous advantage of allowing you to easily and rapidly adjust the scope
using either the MOA marks on the elevation turret or the MOA marks on
the vertical crosshair.

Conversion Chart

Use the following values when

Example

If your arrow has dropped 12
inches on a 50-yard shot, it has
dropped 24 MOA.

12 ÷ .5 = 24 MOA

MOA markings on XBR-1 reticle.

converting fr om inches to MOA s.

1 MOA =

MOA markings on the XBR turret.

1.0 inch at 100 y ard s

.9 inches at 9 0 yard s

.8 inch es at 8 0 yards

.7 inches at 70 yar ds

.6 inch es at 6 0 yard s

.5 inch es at 5 0 yards

.4 inch es at 4 0 yar ds

.3 inch es at 3 0 yard s

.2 inch es at 2 0 yards

Build a Drop Chart in MOAs.

After establishing a 30-yard zero, the second step is to build an MOA
drop chart for your specific crossbow and arrow combination at increasing
distances of 30, 40, 50, 60, 70 yards, etc.

1. Begin by choosing the sample chart and arrow speed that most closely
matches your crossbow (see samples below and on page 22).

2. Dial up the suggested adjustment for the distance you are shooting.

3. Shoot at your target and measure how much the arrow hit above or
below the bullseye in inches.

4. Calculate the MOAs by dividing your measurements by the value
listed in the conversion chart on page 20 and adjust turrets accordingly.

• If arrow strikes low, add your calculated MOA value to chart value.

• If arrow strikes high, subtract your calculated MOA value from chart
value.

5. Shoot again. When you hit the bullseye, record this final MOA
adjustment for future use.

Sample
Drop Charts

Drop Chart in MOAs

325 fps

30 yards 0

40 yar ds 15 MO A

50 yar ds 30 MOA

60 yar ds 46 MOA

70 yard s 63 MOA

Adjustments

Drop Chart in MOAs

360 fps

30 yards 0

40 yar ds 12 MO A

50 yar ds 26 MOA

60 yar ds 41 MO A

70 yard s 55 MOA

80 yar ds 71 MOA

Adjustments

21 20

Drop Chart in MOAs

Sample
Drop Charts

Example Using a 360 f ps Crossbow at a 40-Yard Dist ance

385 fps

30 yards 0

40 yar ds 11 M O A

50 yar ds 23 MOA

60 yar ds 36 MOA

70 yard s 49 MOA

80 yar ds 63 MOA

90 yar ds 77 MOA

100 y ar ds 92 MOA

Adjustments

Drop Chart in MOAs

425 fps

30 yards 0

40 yar ds 7 MOA

50 yar ds 16 MO A

60 yar ds 26 MOA

70 yard s 37 MOA

80 yar ds 48 MOA

90 yar ds 59 MOA

100 y ar ds 71 MOA

Adjustments

Shooting with the initial adjustment as suggested in the sample drop chart
should allow you to hit the target, but you probably won’t hit the bullseye.

1. Dial up 12 MOA on the elevation turret
then aim and shoot at the bullseye using
the reticle crosshair.

2. Measure the distance your arrow hits

Drop Chart in MOAs

360 fps

30 yards 0

40 yar ds 12 MO A

Adjustments

above or below the bullseye in inches.

3. Divide your measurements by .4 to calculate value in MOAs (.4 comes
from the conversion chart on page 20).

• If arrow strikes low, add your calculated MOA value to 12 MOA.

• If arrow strikes high, subtract your calculated MOA value from 12 MOA.

Correcting for Arrow Drop

After building your own MOA drop chart, you can correct for arrow drop by
using either the reticle or the elevation turret correction method.

Arrow Drop Correction Using the Reticle

Compensating for arrow drop and wind drift using the reticle is quick and
easy, and has a big edge in hunting situations because no game spooking
hand motion is required. Simply choose your hold point on the reticle based
on the range and your MOA drop chart and then shoot.

Using a reticle for arrow drop and wind drift compensation has one
important limitation. In second focal plane scopes, such as the Viper XBR,
reticles using drop lines are sensitive to magnification. The marked MOAs
on the XBR-1 reticle are only correctly marked with the scope set at the
highest magnification (10x). At 5x, actual MOAs will be twice what is
marked on reticle; at 2.5x, actual MOAs will be four times what is marked
on the reticle.

Using the following technique, the XBR-1 reticle will allow you to shoot
effectively with your reticle at magnifications of 2.5x, 5x and 10x.

• If you are shooting with the scope set at 10x, all MOA markings on the
reticle are correctly displayed as 10, 20, 30, 40, and 50 MOA.

• If you are shooting with the scope set at 5x, the actual drop values will
be 20, 40, 60, 80, and 100 MOA.

4. Shoot again. When you hit the bullseye, record this final MOA
adjustment for future use.

5. Repeat process with targets set at distances of 50, 60, 70, 80 yards, etc.

TIP: Keep your adjusted MOA drop values handy for quick use in the field.

• If you are shooting with the scope set at 2.5x, the actual drop values
will be 40, 80, 120, 160, and 200 MOA.

Example

Your drop chart indicates you need a 20 MOA holdover to make your shot.
With the scope set at 5x, you should hold on the 10 MOA reticle mark
which yields the actual 20 MOA that you need.

23 22

Arrow Drop Correction Using the Elevation Turret

Using the elevation turret to adjust for arrow drop is slightly slower
than using the reticle, and also entails some hand motion which could
spook game. The advantage to making a turret adjustment is that it is
not sensitive to the scope’s magnification and can be successfully used
at any magnification. Simply turn the turret in the up direction the
number of MOAs indicated on your drop chart, then shoot using the
center crosshair.

Be aware that available turret travel up range may be limited by the
alignment of the crossbow’s scope mounting rail. Most rails should
allow at least 50 MOAs of available up travel when using the XBR’s
elevation turret. If necessary, turret MOAs and reticle MOAs can be
combined to achieve the required drop correction for very long shots.

Once you build your MOA drop chart, it is also possible to etch or
tape a custom elevation turret marked in yards rather than MOAs. A
yardage-marked turret allows quick adjustment in the field without
needing to consult the MOA drop chart. If you are interested in doing
this, please feel free to call our office at [phone] or e-mail
[e-mail] for options and assistance.

mAinTenAnCe

Cleaning

The fully waterproof and fogproof Viper XBR scope 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. Pure alcohol can help remove marks like fingerprints.

Lubrication

All components of the Viper XBR scope 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.

Storage

If possible, avoid storing your scope in direct sunlight or any very hot
location for long periods of time.

Consider adding a custom
elevation turret marked in yards
rather than MOAs.

25 24

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 XBR scope becomes damaged
or defective, Vortex Optics will repair or replace the scope at no charge
to you. If we cannot repair your product, we will replace it with a
product in perfect working order of equal or better physical condition.
Call Vortex Optics at 800-426-0048 for prompt, professional, and
friendly service.

Vortex Optics

2120 West Greenview Drive

Middleton, WI 53562

[e-mail]

Visit www.vortexoptics.com for more information. Canadian customers
may visit www.vortexcanada.net for customer service information.

Note: The VIP warranty does not cover loss, theft or deliberate damage
to the product.

Vortex Optics believes strongly in responsible, ethical hunting.
Although scopes can make long distance shots much easier, there
are still many other variables, such as wind, affecting every shot.
It is important for hunters shooting at long distances to learn
their personal, effective range, particularly in windy conditions,
and to not shoot beyond those distances.

Unlimited

Unconditional

Lifetime Warrant y

27 26