The .308 Winchester, a renowned cartridge for its accuracy and versatility, is popular among hunters, target shooters, and military personnel. Understanding its trajectory is crucial for accurate shot placement at various distances. This article provides a comprehensive look at .308 Win trajectory, considering factors influencing bullet flight and offering a practical guide for using trajectory data. Note that this is a general guide, and actual trajectory will vary based on several factors detailed below. Always consult your specific ammunition's ballistic data for the most accurate results.
Factors Affecting .308 Winchester Trajectory
Before diving into sample trajectory data, it's essential to understand that several factors influence how a .308 Winchester bullet flies:
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Bullet Weight: Heavier bullets generally have a flatter trajectory but lower velocity. Lighter bullets possess higher velocity but a more curved trajectory.
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Bullet Shape & Construction: The ballistic coefficient (BC) of a bullet significantly impacts its trajectory. A higher BC indicates less air resistance, resulting in a flatter trajectory. Different bullet designs (e.g., boat-tail vs. flat-base) also affect BC.
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Muzzle Velocity: Higher muzzle velocity translates to a flatter trajectory at longer ranges. This is heavily influenced by the firearm, ammunition, and environmental conditions.
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Altitude: Higher altitudes result in lower air density, causing the bullet to travel farther.
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Temperature: Air density varies with temperature. Hotter air is less dense, leading to a slightly flatter trajectory, while colder, denser air causes a steeper trajectory.
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Wind: Wind is the most significant unpredictable factor influencing bullet flight. Crosswinds cause drift, while headwinds and tailwinds affect range.
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Rifle Twist Rate: The rate of twist in your rifle barrel can affect bullet stability and accuracy, impacting trajectory at longer ranges.
Sample .308 Winchester Trajectory Table (Approximate)
This table provides approximate trajectory data for a 150-grain .308 Winchester bullet with a ballistic coefficient of 0.450, fired from a rifle with a muzzle velocity of 2700 feet per second (fps). This is not a substitute for the ballistic data provided by your specific ammunition manufacturer. Conditions are assumed to be standard (sea level, 59°F, no wind).
| Distance (yards) | Bullet Drop (inches) | Velocity (fps) |
|---|---|---|
| 100 | -2.7 | 2450 |
| 200 | -10.8 | 2220 |
| 300 | -24.3 | 2000 |
| 400 | -43.2 | 1800 |
| 500 | -67.5 | 1620 |
| 600 | -97.2 | 1450 |
| 700 | -132.3 | 1300 |
| 800 | -173.0 | 1160 |
| 900 | -218.0 | 1040 |
| 1000 | -269.0 | 930 |
Remember: This table is an estimation. Actual results will vary.
Utilizing Trajectory Data
Understanding bullet trajectory is vital for accurate long-range shooting. This involves:
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Zeroing your rifle: This is the process of adjusting your scope's aim to compensate for bullet drop at a specific distance (often 100 or 200 yards).
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Using a ballistic calculator: These tools factor in all the variables mentioned above to provide precise trajectory data for your specific ammunition and conditions.
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Practicing: Regular practice at various distances is essential to develop your ability to accurately estimate holdovers and windage adjustments.
Conclusion
The .308 Winchester cartridge remains a popular choice for its versatility and accuracy. However, effective long-range shooting with this caliber requires a solid understanding of trajectory and the factors influencing it. Always prioritize safety and utilize the appropriate resources, including your ammunition's ballistic data and ballistic calculators, to maximize accuracy and performance.
