The question of whether to "chase the bullet" when sighting in a scope is a common one among both new and experienced shooters. The short answer is: generally no, you should not actively chase the bullet. However, understanding the nuances of this practice is crucial for accurate zeroing. This article will delve into the complexities of scope sighting, explaining why chasing the bullet is often counterproductive and outlining the best practices for achieving a precise zero.
Understanding the Sighting-In Process
Sighting in a scope involves adjusting the scope's turrets to align the point of impact (POI) of your bullets with your point of aim (POA). This is a systematic process, typically involving several shots at various distances, followed by adjustments based on the observed bullet impacts.
The Impact of Environmental Factors
Before we discuss chasing bullets, it's vital to understand that several environmental factors can influence bullet trajectory. These include:
- Wind: Wind can significantly deflect a bullet's path, especially at longer ranges.
- Temperature: Temperature affects both the bullet's velocity and the air density, impacting its trajectory.
- Humidity: High humidity can also slightly affect bullet flight.
- Altitude: Higher altitudes result in thinner air, altering bullet behavior.
Ignoring these factors when sighting in can lead to inaccurate conclusions and frustration.
The Myth of "Chasing the Bullet"
The idea of "chasing the bullet" implies making continuous, small adjustments to the scope after each shot, attempting to progressively move the POI closer to the POA. This approach is often flawed because:
- Cumulative Errors: Small errors in each adjustment compound over multiple shots, leading to a less accurate zero than a more methodical approach.
- Overcorrection: Chasing the bullet can easily result in overcorrection, requiring more adjustments and potentially leading to a less accurate final zero.
- Ignoring Systemic Issues: Chasing the bullet might mask underlying issues with your shooting technique or equipment, preventing you from identifying and correcting them.
The Recommended Approach: A Methodical Process
A more effective method for sighting in a scope involves a three-shot grouping approach:
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Initial Shot Group: Fire three shots at your target. Note the group's center. This provides a baseline for your adjustments.
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Adjustments: Based on the group's center, adjust the scope's windage and elevation turrets according to your firearm's instruction manual. Many manufacturers provide clear instructions and conversion charts for their scopes. Remember to record your adjustments!
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Second Shot Group: Fire another three-shot group. Evaluate the new group's center compared to your point of aim.
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Refine Adjustments (if necessary): If the second group still isn't centered on your point of aim, make smaller adjustments and repeat the process until you achieve the desired accuracy.
This systematic approach minimizes cumulative errors and allows for more precise zeroing.
Case Study: A Common Sighting-In Scenario
Let's say your initial three shots create a group 3 inches to the left and 2 inches high of your point of aim at 100 yards. Instead of making small adjustments after each shot, use the following steps:
- Identify the average deviation: The group is 3 inches left and 2 inches high.
- Consult your scope's adjustment instructions: Determine the click value for your scope (e.g., 1/4 MOA per click).
- Calculate the required adjustments: Adjust your windage to the left, and your elevation down, based on the click value and deviation from your point of aim.
- Shoot a second three-shot group to verify.
Maintaining Your Zero
Once you've zeroed your scope, it's crucial to maintain that zero. Avoid impacts that might damage the scope, and ensure that your rifle remains properly maintained.
Conclusion: Precision Over Haste
While the term "chasing the bullet" might sound intuitive, it's often a less accurate method for sighting in a scope than a systematic, methodical approach. By understanding the influencing factors, employing a three-shot grouping technique, and following proper adjustment procedures, shooters can achieve a precise and repeatable zero, leading to more accurate shooting. Remember to record your adjustments! This detailed approach ensures accuracy and minimizes frustration throughout the sighting-in process.