Vortex Optics RAZOR HD 5-20X50 RIFLESCOPE — First Focal Plane - Manual (Page 2)

2
2 3
MRAD Subtensions
The EBR-2B mrad reticle is based on the milliradian
(or mrad for short), a form of angular measurement.
This measurement is similar in concept to a degree
although much finer. A degree is 1/360th of a circle; a
milliradian is 1/6283th of a circle.
When used in a first focal plane riflescope such as the Vortex
Razor riflescope, the mrad subtensions of the EBR-2B reticle
are valid at all magnification levels. This means the shooter can
use the magnification level most appropriate for the situation
and still have effective holdover and windage reference marks.
This is extremely valuable in a high-stress situation, as the
shooter does not have to remember to set the scope to one
particular magnification to get valid holdovers—an action
necessary with the more common second focal plane reticles.
Most shooters are familiar with the minute-of-angle
(MOA) system commonly used in hunting riflescopes.
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. When comparing MOAs and
mrads, 3.44 MOAs is equal to 1 mrad. These angular
measurements are used for ranging and to correct for
bullet trajectory drop in riflescopes.
Both milliradian and MOA measurements are effective
for ranging and bullet trajectory drop compensation in
reticle designs. However, the milliradian method used in
the EBR-2B reticle has some important advantages over an
MOA method. The primary benefit is that once learned,
it is much simpler and faster to use. The milliradian system
will also be very easy for shooters familiar with the metric
system and for those shooters with previous training in
using mil dot reticles.
Fine crosshairs
subtend .06 mrads
Heavy crosshairs
subtend .8 mrads
.2 mrads 1 mrad
Center gap subtends .07 mrads
Large dots
subtend .09 mrads
Small dots
subtend .06 mrads
.5 mrad
1 mrad .2 mrads