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(Figure 1) This is the main sheet of the Exbal program, which is similar to other current ballistic programs. When the necessary data has been completed, the Calculate button is keyed and the results are displayed.

(Figure 1) This is the main sheet of the Exbal program, which is similar to other current ballistic programs. When the necessary data has been completed, the Calculate button is keyed and the results are displayed.

Night Force Data Sheets

(Figure 2) The Nightforce NP-R2 reticle's hashmark subtension has been input at 2 MOA. At the top, the scope's power is input at the magnification 2 MOA is subtended. This is normally at max power for a second focal plane reticle. At "Point Blank Target Height" you input a kill zone you believe conservative. Hit "Calculate" and the distances each hashmark will hit is displayed along with the distances at which the bullet hits 4" above and 4" below. On the right, you can tweak the zero until you're satisfied with the result. Alternatively, you can tweak the scope's power.

(Figure 2) The Nightforce NP-R2 reticle's hashmark subtension has been input at 2 MOA. At the top, the scope's power is input at the magnification 2 MOA is subtended. This is normally at max power for a second focal plane reticle. At "Point Blank Target Height" you input a kill zone you believe conservative. Hit "Calculate" and the distances each hashmark will hit is displayed along with the distances at which the bullet hits 4" above and 4" below. On the right, you can tweak the zero until you're satisfied with the result. Alternatively, you can tweak the scope's power.

output information in 25-yard increments to 1,000 yards or more. Bullet weight and ballistic coefficient can be obtained from the manufacturer. Scope height above the bore is just the distance from the center of the bolt or receiver to the center of the scope. Environmental conditions can be obtained from any instrument giving temperature and barometric pressure.

The impact point of each hashmark can be determined from this printout with a bit of math and some work. However, a ballistic program called Exbal does this for you along with several other things you must know (refer to Figure 1). Once the overall table of the bullet's flight, wind hold, drop, etc has been calculated, a drop down table under "Utility Functions" has a link called Ballistic Reticle Analysis (refer to Figure 2). Clicking on that will produce a table. At the top left, the scope's power is input set for the subtension you found by one of the three methods given above. Next, that subtension is input in the boxes below.

Once the subtension of the hashmarks is input, select a zero distance, say 100 yards, and hit calculate. The box to the right of the hashmark subtension will then display the distances each hashmark will hit if the rifle is sighted in at 100 yards. Near the top middle of the table, you will see an input allowing you to select a kill zone circle you want to hit. For example, if you are hunting deer, you might decide if you can hit an 8" circle, you will hit the kill zone of a deer. So selected, the table tells you both the exact distance the bullet will hit on the hashmark, but also at what distance you will be 4" above and 4" below that point. Sierra calls this Point Blank Range in their manual.

You might decide the distances the hashmarks hit will be difficult to remember, and you would rather have them hit closer to 100-yard intervals. Near the lower, right side of the table, a key allows you to optimize the hashmarks. By working with the table, you will find a power, a kill zone size, and a zero to best suit your needs.

Not everyone has a chronograph. Thus, you probably entered your best guess, something provided by the manufacturer of your ammo, or a loading manual if you handload. You can back into the correct velocity and print out of the Ballistic Reticle Analysis by shooting at 100-yard intervals to about 500 yards and noticing the impact center of 5-round groups. Tweaking both the velocity in the ballistic software and the Ballistic Reticle Analysis table, you will come up with a very precise hashmark table.

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