Vortex 4-16x50 EBR-1 MOA reticle manual - Euro Optics Ltd.

SECOND FOCAL PLANEVortex EBR-1 MOA ReticlePRECISIONSHOOTINGTACTICALEBR-1 MOA Manual4–16x50 RiflescopeDesigned to maximize long distance shooting andranging abilities,the EBR-1 MOAreticle can beused to effectivelydetermine ranges,holdovers, windagecorrections andmoving target leads.Ultra precisionlaser etching onthe glass reticle ensures that minute of angle (MOA)specifications can be kept to the tightest tolerancespossible. The fine center crosshair subtensions on theEBR-1 MOA reticle were carefully chosen to providethe optimum balance between precision aiming and lowlight visibility.1

MOA SubtensionsThe EBR-1 reticle is based on minute-of-angle (MOA)subtensions. Many shooters areEstimating MOAvery familiar with the MOAAlthough 1 MOA is verysystem used in hunting riflescopes.commonly corresponded to 1MOA measurements are based oninch at 100 yards, this is notdegrees and minutes: 360 degreesquite correct 1 MOA at 100in a circle, 60 minutes in a degreeyards equals 1.05 inches.for a total of 21,600 minutes.Calling 1 MOA an inch perThese angular measurements100 yards may be acceptableare used to estimate range and at shorter distances, but itcorrect for bullet trajectory will cause a fi ve percent errordrop in riflescopes. 1 MOA will in ranging and holdovercorrespond to 1.05 inches at a 100 adjustments. This will resultyard distance, 2.1 inches at 200 in missed shots at longeryards, 3.15 inches at 300 yards, distances.and so on.In this second focal plane riflescope, the listed MOAsubtensions are only valid at the highest magnification ofthe scope. However, by understanding the relationship ofmagnification and subtensions, ranging, holdovers and winddrift can still be calculated at partial magnifications. Ifmagnification is set at 1/2 of full magnification, subtensionvalues will be two times the manual listed spec. Ifmagnification is set at 1/3 full magnification, subtension valueswill be three times the manual listed spec. If magnification isset at 1/4 of full magnification, subtension values will be fourtimes the manual listed spec.EBR-1 Reticle SubtensionsTo help calculate ranges, holdovers and wind drifts atmagnifications other than full power, the Viper PST4–16x50 riflescope uses a dual number marking system onthe magnification dial. The 1x, 2x, 3x, and 4x subtensionmultiplier markings on the back side of the magnificationnumbers can be used in conjunction with the reticle to helpcalculate distances and holdovers at varying magnifications.Heavy crosshairsubtends 1.5 MOAModel4–16x50Reticlesubtensionsvalid at 16x5 MOA 2 MOARiflescopeMagnification16x8x5.3x4xFine crosshairsubtends .1 MOA2 MOA4 MOAs6 MOAs8 MOAsGap subtends1.5 MOASubtension Changes with MagnificationReticleMultiplier1x2x3x4xActual Subtensionof 2 MOA Reticle Space2 3

RangingMOA measurements are very effective for rangingusing a simple formula. To use this formula, theshooter needs to know the size of the target or nearbyobject in inches.ExampleMOA Ranging FormulaTarget Size (Inches) x 95.5Measured MOAs=Range (Yards)Using either the vertical or horizontal MOA scale,place the reticle on a target of known dimensions andread the number of MOAs spanned. You will obtainmaximum accuracy in ranging by calculating exactMOA measurements. MOAs should be estimated in1/4s if possible.Accurate measuring will depend on a very steadyhold. The rifle should be solidly braced using a rest,bipod or sling when measuring. Once you have anaccurate MOA reading, use the formula to calculatethe distance.Ranging a man (39 inches from groin to top of head)at 6 MOAs yields 621 yards.39 x 95.5= 621 Yards6 MOANote: In the MOA ranging formula, a shooter may substitute 100 for95.5 in the interest of speedier calculations. Be aware that this willproduce a fi ve percent over-estimation error of the yardage distanceobtained.4 5

Elevation HoldoversOnce the distance has been calculated using theEBR-1 MOA reticle or a laser rangefinder, theEBR-1 can be used for rapid holdover correction forbullet drop of the cartridge being used. To get themost benefit out of the EBR-1 equipped riflescope,Vortex Optics highly recommends shooters learntheir bullet drop numbers in MOAs rather thaninches.ExampleSince the EBR-1 reticle is scaled in 2 MOAincrements, it is an easy job to quickly select thecorrect drop reference line once the shooter knowsthe bullet drops in MOAs. If the shooter prefers todial come ups for bullet drop using the elevationknob, knowing bullet drops in MOAs rather thaninches will allow for much faster adjustments as theMOAs can be quickly read on the elevation knob.17.5 MOA reticle holdover for 625-yard shot. No wind.6 7

Windage and Moving TargetsThe EBR-1 MOA reticle is highly effective whenused for wind and moving target leads. Using thereticle for effective windage and moving targetleads will require thorough knowledge of yourweapons system’s ballistic performance undervarying conditions and experience in readingwind strengths and target speeds. As in bulletdrops, it is important for the shooter to learna particular weapon’s windage/moving targetcorrections in MOAs rather than inches. Alwayshold the reticle into the wind.Example10 mph windFull value wind at 90 degreesBasic windage correction on center crosshairWhen dialing elevation come ups, the centerhorizontal crosshair will be used for windage ormoving lead corrections.3 MOA reticle windage correction for 400-yard shot in 10 mphcrosswind using center crosshair. Elevation adjustment alreadydialed into rifl escope.8 9

Basic windage correction using drop line on reticleWhen using the reticle for elevation correction ratherthan dialing, the MOA marks on the center horizontalcrosshair can still be used to help visually referencewindage corrections. Remember to hold the reticle intothe wind.ExampleBasic moving lead correctionWhen estimating moving target leads, the MOA markson the center horizontal crosshair can be used. Estimatingmoving target leads will require knowing yardage distance,wind speed, moving target speed, and total bullet flight time(including rifle lock time). Bullet flight times can be roughlycalculated based on fps velocities or a ballistic calculator.Note: Correctly estimating moving leads is very diffi cult and requiresconsiderable practice and knowledge beyond the scope of this manual.Example20 mph windFull value wind at 90 degreesWalking Direction8 MOA reticle windage correction for 500-yard shot in 20 mphcrosswind using 12 MOA reticle drop line.9.4 MOA reticle correction for a man walking 3 mph at a distance of800 yards. No wind. Total bullet time of fl ight from trigger pull 1.5seconds during which man travels 6.6 feet. Elevation already dialedinto turret.10 11

Vortex Service and Repair PolicyUnconditional Lifetime WarrantyVortex Optics wants you to shootand use your Viper PST riflescopeunder any conditions withcomplete confidence—that’s whyour warranty is straightforwardand simple:• Fully transferableUnconditional LifetimeWarrantyvortexoptics.com• No warranty card needed• No receipt neededRest assured, if this riflescope should ever require repair, allyou need to do is contact Vortex for absolutely free service.Call 800-426-0048 or e-mail service@vortexoptics.com.Vortex Optics2120 West Greenview DriveMiddleton, Wisconsin 53562USAPatent PendingDual Use: Shooting Tactical / HuntingManual #R-416S1-A12