In the world of precision shooting, understanding the ballistic performance of your ammunition is critical. However, translating that data—often found on the side of your ammo box—into actionable adjustments on your riflescope can sometimes feel like deciphering an ancient script. This guide will illuminate the path from reading bullet drop charts to making precise elevation adjustments in either MOA (Minute of Angle) or MIL (Milliradian), ensuring your rounds find their mark, regardless of distance.
Into the Numbers: A Case Study with the .30-06 Springfield
Let's ground our exploration in reality by using Federal Ammunition Power-Shok Rifle .30-06 Springfield as our example. Here's the drop chart from the manufacturer:
| Distance (yds) | Bullet Drop (inches) |
|---|---|
| 100 | 1.8 |
| 200 | 0 |
| 300 | -8.0 |
| 400 | -23.8 |
| 500 | -49.4 |
Notice the data assumes a 200-yard sight-in. To tailor this to a 100-yard zero—preferable for many shooters—we recalculated the drops:
| Distance (yds) | Bullet Drop (inches) |
|---|---|
| 100 | 0 |
| 200 | 1.8 |
| 300 | -9.8 |
| 400 | -25.6 |
| 500 | -51.2 |
With our customized drop table, let's dive into converting these figures to dial adjustments on your scope.
(notice we moved the -1.8 from 100 to 200, and added that same value to the rest of the inch-drop values)
Converting Inches to MOA - Making Sense of Dial Adjustments
To translate inch drops to MOA, we'll use the fact that 1 MOA roughly equals 1.047 inches at 100 yards. Here’s how:
- Divide the distance by 100 to find the whole number for that distance
- Multiply the whole number by 1.047 to gain the MOA size at that distance.
- Take the bullet drop in inches and divide by the MOA's inch value.
EXAMPLE
- 300yds / 100 = 3
- 3 x 1.047 = 3.141
- -9.8 / 3.141 = -3.1
This results in the following table for a 100-yard zero:
| Distance (yds) | MOA Dial Settings |
|---|---|
| 100 | 0 |
| 200 | -0.85 |
| 300 | -3.1 |
| 400 | -6.1 |
| 500 | -9.7 |
The MIL Method - An Alternate Path
For those whose scopes adjust in MILs rather than MOA, the process mirrors our steps above. Given 1 MIL equals 3.6 inches at 100 yards, we calculate our dial settings similarly:
- Divide the distance by 100 to find the whole number for that distance
- Multiply the whole number by 3.6 to gain the MIL size at that distance.
- Take the bullet drop in inches and divide by the MIL's inch value.
EXAMPLE
- 300yds / 100 = 3
- 3 x 3.6 = 10.8
- -9.8 / 10.8 = -0.9
Our example yields:
| Distance (yds) | MIL Dial Settings |
|---|---|
| 100 | 0.0 |
| 200 | -0.25 |
| 300 | -0.9 |
| 400 | -1.7 |
| 500 | -2.8 |
Conclusion - Aiming for Accuracy
By translating the ballistic drop of ammunition into the language of your riflescope—be it MOA or MIL—you empower yourself with precise, distance-specific adjustments. This calculated approach will transform the frustrating guesswork of doping the wind and estimating range into a series of confident, clear cuts adjustments.
Remember, the essence of sharpshooting lies not just in your equipment or posture but in your understanding of how a bullet traverses the space between barrel and bullseye. Armed with this knowledge, you're not just shooting; you're tactically engaging with every shot.
Happy shooting, and may your adjustments be ever accurate!
John Boyette