First Focal Plane Reticles

First focal plane (FFP) reticles are located near the windage and elevation turrets in front of the image-erecting and magnifying lenses. This style of reticle will visually grow and shrink as you change the magni cation. The main advantage of an FFP reticle is that the reticle subtensions used for ranging, holdovers, and wind drift corrections are consistent at all magnifications. The reticle is heavier at higher magnifications and finer at lower magnifications.

The Subtension Scale:

MRAD Adjustments

An MRAD will subtend 3.6 inches at a distance of 100 yards. Viper PST riflescopes with MRAD adjustments use .1 MRAD clicks which subtend .36 inches at 100 yards / 1 cm at 100 meters, .72 inches at 200 yards /2 cm at 200 meters, 1.08 inches at 300 yards / 3 cm at 300 meters, etc.

Windage and Elevation Adjustments

Vortex Viper PST riflescopes incorporate precision finger adjustable elevation and windage dials with audible clicks.

 To make adjustments:

1. Turn the adjustment knob in the appropriate direction: Up/Down or Left/Right as indicated by the arrows.

2. Following the directional arrows, turn the knobs in the direction you wish the bullet’s point-of-impact to go to.


MRAD Adjustments

With each click of the Viper PST moving the point-of-impact .1 MRAD, four clicks will move the bullet’s point-of-impact 1.44 inches at a 100 yard sight-in distance. At 100 meters, four clicks will move the point-of-impact four centimeters.

RZR Zero Stop

Vortex Viper PST riflescopes incorporate the RZR Zero Stop feature. After the rifle is sighted in, the RZR Zero Stop allows fast, sure return to the original zero point when large multi-revolution elevation corrections have been dialed into the riflescope.

Without a zero stop, the shooter must pay very careful attention when dialing large corrections needing multiple revolutions of the elevation knob. If the shooter loses track of the number of revolutions, the original zero point may become lost. Because of the RZR Zero Stop, the elevation knob on Vortex Viper PST scopes can be quickly spun back to the original zero without having to carefully count revolutions.

Once the RZR Zero Stop is set, the elevation knob will stop turning at the original zero point when being returned from a temporary elevation correction.


XD™ Lens ElementsExtra-low dispersion (XD) glass increases resolution and color fidelity, resulting in crisp, sharp images.
XR™ Fully Multi-CoatedProprietary coatings increase light transmission with multiple anti-reflective coatings on all air-to-glass surfaces.
First Focal Plane ReticleScale of reticle remains in proportion to the zoomed image. Constant subtensions allow accurate holdover and ranging at all magnifications.
Glass-etched ReticleProtected between two layers of glass for optimum durability and reliability.
Illuminated ReticleProvides precise aiming under low-light conditions.


Tube Size30 mm diameter.
Single-Piece TubeMaximizes alignment for improved accuracy and optimum visual performance, as well as ensures strength and waterproofness.
Aircraft-Grade AluminumConstructed from a solid block of aircraft-grade aluminum for strength and rigidity.
WaterproofO-ring seals prevent moisture, dust and debris from penetrating the riflescope for reliable performance in all environments.
FogproofArgon gas purging prevents internal fogging over a wide range of temperatures.
ShockproofRugged construction withstands recoil and impact.
Hard Anodized FinishHighly durable low-glare matte finish helps camouflage the shooter’s position.
ArmorTekUltra-hard, scratch-resistant coating protects exterior lenses from scratches, oil and dirt.
Tactical-Style TurretsExposed turrets provide fast, accurate and easily read elevation and windage adjustments.


RZR Zero StopZero Stop mechanism prevents the turret from dialing below sight-in range.
Precision-Force Spring SystemUses premium components in the erector-spring system to ensure maximum repeatability and ease of adjustment.
Precision-Glide Erector SystemUses premium components in the zoom lens mechanism to ensure smooth magnification changes under the harshest conditions.


Radius BarFiber optic turret rotation indicator provides a highly visible and tactile point of reference for turret rotations. US Patent 7,937,879
Fast Focus EyepieceAllows quick and easy reticle focusing.
Built-In Accuracy FeaturesMatching (MRAD or MOA) turrets and reticles facilitate fast and accurate shooting at extended ranges. The patented fiber optic Radius Bar visually assists tracking turret rotations. US Patent 7,937,879


Magnification2-10 x
Objective Lens Diameter32 mm
Eye Relief3.2 in
Field of View58.3-11.7 feet/100 yards
Tube Size30 mm
Turret StyleTactical
RZR Zero Stop
Adjustment Graduation.1 MRAD
Travel per Rotation10 MRAD
Max Elevation Adjustment26 MRAD
Max Windage Adjustment26 MRAD
Parallax Setting20 yards to Infinity
Length12.75 inches
Weight26.3 ounces

Additional information

Weight1.6 lbs


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