Vortex Optics VIPER PST 4-16X50 RIFLESCOPE User Manual

RIFLESCOPE

Second Focal Plane | Uncapped Turrets

4-16x50 ebr-1 RETICLE (moa)

Dual Use: Shooting Tactical / Hunting

US Patent 7,937,879

RIFLESCOPE

The Vortex® EBR-1 MOA Reticle

Designed to maximize long distance shooting and ranging abilities, the EBR-1 MOA reticle for the Viper®PSTTM 4–16x50 riflescope can be used to effectively determine ranges, holdovers, windage corrections and moving target leads. Ultra precision laser etching on the glass reticle ensures that minute of angle (MOA) specifications can be kept to the tightest tolerances possible. The fine center crosshair subtensions on the EBR-1 MOA reticle were carefully chosen to provide the optimum balance between precision aiming and low light visibility.

Note: Reticle images shown in this manual are for representation only—images vary between scope models depending on magnification and reticle plane.

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Estimating MOA

Although 1 MOA is very commonly corresponded to 1 inch at 100 yards, this is not quite correct. 1 MOA at 100 yards equals 1.05 inches. Calling 1 MOA

an inch per 100 yards may be acceptable at shorter distances, but it will cause a five percent error in ranging and holdover adjustments. This will result in missed shots at longer distances.

MOA Subtensions

The EBR-1 reticle is based on minute-of-angle (MOA) subtensions. MOA measurements are based on degrees

and minutes: 360 degrees in a circle, 60 minutes in a degree for a total of 21,600 minutes. These angular measurements are used to estimate range and correct for

bullet trajectory drop in riflescopes. 1 MOA will correspond to 1.05 inches at a 100 yard distance, 2.1 inches at 200 yards, 3.15 inches at 300 yards, and so on.

In the Viper PST second focal plane riflescopes, the listed MOA subtensions of the EBR-1 reticle are only valid at the highest magnifications of the scope.

However, by understanding the relationship of magnification and subtensions,

ranging, holdovers, and wind drift can still be calculated at partial magnifications. Here are some examples:

•If the magnification is set at 1/2 the full magnification, subtension values will be two times the spec listed in the manual.

•If the magnification is set at 1/3 the full magnification, subtension values will be three times the spec listed in the manual.

•If the magnification is set at 1/4 the full magnification, subtension values will be four times the spec listed in the manual.

RIFLESCOPE

EBR-1 MOA Reticle Subtensions

Fine crosshair Heavy crosshair subtends .1 MOA subtends 1.5 MOA

5 MOA	2 MOA		Gap subtends
			1.5 MOA

Subtension Changes with Magnification

4–16x50 Reticle Subtensions

	(Valid at 16x)
RIFLESCOPE	ACTUAL SUBTENSION OF
MAGNIFICATION	2 MOA RETICLE SPACE
16x	2 MOA
8x	4 MOA
5.3x	6 MOA
4x	8 MOA

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