The term "20 MOA base zero at 100 yards" might sound intimidating to new shooters, but understanding it is crucial for accurate long-range shooting. This article will break down what it means, why it's important, and how to achieve it. We'll explore the concepts of minute of angle (MOA), base zeroing, and the practical application of this technique for improved accuracy at longer distances.
Understanding Minute of Angle (MOA)
A minute of angle (MOA) is a unit of angular measurement. One MOA equals approximately 1 inch at 100 yards. This means that if your bullet impacts 1 inch high or low, or left or right of your point of aim at 100 yards, that's a one MOA error. Understanding MOA is fundamental because it allows for consistent and predictable adjustments to your scope's aiming point.
MOA and Long-Range Shooting
In long-range shooting, even small errors in aiming translate to significant misses at longer distances. A 1 MOA error at 100 yards becomes a 2 MOA error at 200 yards (approximately 2 inches), and a 3 MOA error at 300 yards (approximately 3 inches), and so on. Precise MOA adjustments are crucial for making accurate shots at extended ranges.
What is Base Zeroing?
Base zeroing is the process of setting your rifle's scope to have a point of impact (POI) that aligns precisely with your point of aim (POA) at a specific zeroing distance, which is often 100 yards. This creates a "zero" or baseline for making adjustments. With a 100-yard zero, you have a known starting point for calculating adjustments at different distances.
Why 100 Yards?
100 yards provides a suitable balance. It's a manageable distance for many shooters and offers enough range to properly assess the point of impact. Also, it allows for easier adjustments as many rifles have a natural slight trajectory drop between close ranges and longer ranges.
The Significance of a 20 MOA Base
A 20 MOA (Minute of Angle) base is an elevated rail system for your scope. It's designed to provide you with sufficient upward adjustment on your scope. Many long-range shooting scenarios require significant elevation adjustments to compensate for bullet drop at longer ranges. A 20 MOA base is usually recommended.
Why 20 MOA is Important for Long-Range Shooting
A standard scope has limited vertical adjustment. A 20 MOA base essentially adds 20 MOA to the scope's total vertical adjustment, thus allowing for shots at significantly longer ranges. Without the additional vertical adjustment offered by the 20 MOA base, you might run out of adjustment in your scope turrets before reaching your target distance.
Achieving 20 MOA Base Zero at 100 Yards
Achieving a 20 MOA base zero at 100 yards involves a series of steps:
- Mount your scope: Securely mount your scope with the 20 MOA base on your rifle.
- Initial sighting: Roughly sight in your rifle at a shorter range (e.g., 25 yards). This gets you on paper so you don't waste ammo at longer ranges
- Zero at 100 yards: Move to a 100-yard range and fire a group of shots.
- Adjustments: Based on where your group lands at 100 yards, adjust your scope's windage and elevation turrets to center your POI. Remember, each click on your scope corresponds to a specific MOA adjustment, usually 1/4 MOA or 1/8 MOA.
- Verify zero: After adjustments, confirm your zero by firing another group. Repeat the process until you are satisfied.
- Record your settings: Note your scope's elevation and windage settings for future reference.
Case Study: A Practical Example
Let's say you're using a rifle with a 20 MOA base and a scope that has 1/4 MOA clicks. After firing a group at 100 yards, your shots land 2 inches high and 1 inch to the left. To correct this:
- Elevation: You need to adjust 2 MOA down (2 inches at 100 yards = 2 MOA). Since each click is 1/4 MOA, you'll need to make 8 clicks down (2 MOA / 0.25 MOA/click = 8 clicks).
- Windage: You need to adjust 1 MOA to the right. This means 4 clicks to the right.
After making these adjustments, verify your zero by firing another group.
Conclusion
Setting up a 20 MOA base zero at 100 yards is a fundamental step in achieving consistent accuracy in long-range shooting. Understanding MOA, the function of a 20 MOA base, and the process of zeroing allows you to make precise adjustments, maximizing your shooting performance. Always practice safe firearm handling techniques and remember consistent practice is key to becoming proficient.