The 7mm-08 Remington is a popular hunting cartridge known for its accuracy and moderate recoil. Paired with Hornady's 139 grain SST (Super Shock Tip) bullet, it becomes a potent combination for a wide range of game. This post delves into the ballistics of this specific combination, exploring its performance characteristics and suitability for various hunting scenarios. We'll examine factors influencing its trajectory, energy retention, and overall effectiveness. Understanding Hornady 7mm-08 139 gr SST ballistics is crucial for hunters aiming to maximize their accuracy and hunting success.
Understanding 7mm-08 Ballistics: A Foundation
Before we dive into the specifics of the Hornady 139 gr SST, let's establish a baseline understanding of 7mm-08 ballistics in general. This cartridge offers a fantastic balance of power and accuracy, making it a favorite for medium-sized game like deer, antelope, and even some larger species depending on shot placement. Key factors influencing 7mm-08 ballistics include:
- Barrel Length: Longer barrels generally yield higher velocities. A 22-inch barrel is common, but longer or shorter barrels will alter the velocity and thus the trajectory.
- Powder Charge: The amount of powder used significantly impacts velocity and pressure. Following manufacturer's recommendations is crucial for safety and optimal performance.
- Bullet Construction: The bullet's design (e.g., boat-tail, hollow point, solid) impacts its ballistic coefficient (BC), influencing its trajectory and energy retention over distance. The Hornady SST, with its polymer tip, is designed for expansion and controlled penetration.
- Environmental Conditions: Temperature, altitude, and humidity all affect bullet performance. Higher altitudes and temperatures tend to reduce velocity slightly.
Bullet Construction: Hornady 139 gr SST
The Hornady 139 gr SST is a popular choice for the 7mm-08. Its design features:
- Super Shock Tip (SST): The polymer tip initiates expansion at lower velocities than traditional bullets. This is crucial for maintaining consistent performance even at longer ranges where velocity might be diminished.
- Interlock Ring: This feature secures the core and jacket, promoting reliable expansion and controlled penetration even through dense bone.
This combination of features makes the Hornady 139 gr SST a highly effective hunting bullet. The polymer tip ensures reliable expansion for quick kills, while the interlock prevents fragmentation, leading to better penetration and energy transfer.
Hornady 7mm-08 139 gr SST Ballistic Data
Precise ballistic data will vary based on the factors mentioned above (barrel length, powder charge, environmental conditions). However, we can use typical data as a reference point. These values are approximate and should be considered for planning purposes only. Always consult your reloading manual or chronograph data for precise information for your specific setup.
| Distance (yards) | Velocity (fps) | Energy (ft-lbs) | Trajectory (inches) |
|---|---|---|---|
| 0 | 2600 | 2400 | 0 |
| 100 | 2350 | 1950 | -1 |
| 200 | 2100 | 1550 | -6 |
| 300 | 1875 | 1200 | -16 |
| 400 | 1650 | 900 | -30 |
| 500 | 1450 | 650 | -50 |
Note: These values are estimations. Actual values will vary.
This table provides a general idea of the 139 gr SST's performance. Notice how energy drops off significantly past 300 yards. This highlights the importance of accurate shot placement at longer ranges.
Factors Affecting Ballistic Performance
Several factors can subtly influence the values in the above table. For example:
- Twist Rate: The rate of twist in your rifle barrel affects bullet stability. A faster twist rate is generally better for longer, heavier bullets like the 139 gr SST.
- Sight-in Distance: How you sight in your rifle will influence the trajectory at different distances.
- Environmental Conditions: Wind speed and direction have a significant impact, especially at longer ranges.
Case Study: Hunting with the 7mm-08 139 gr SST
Several hunters have reported excellent results using the 7mm-08 139 gr SST on whitetail deer and similar sized game. The controlled expansion of the SST coupled with sufficient penetration makes it effective for clean kills even on quartering shots. However, it's critical to note that proper shot placement remains paramount for ethical and successful hunts. Poor shot placement can result in wounded animals, regardless of the cartridge or bullet used.
Conclusion: Optimizing your 7mm-08 139 gr SST Ballistics
The Hornady 7mm-08 139 gr SST offers excellent ballistic performance for many hunting situations. Understanding the factors that influence its trajectory, energy, and expansion is critical for maximizing its potential. Always prioritize accurate shot placement, use appropriate sighting techniques, and consider environmental conditions. This approach will significantly improve your chances of success and contribute to ethical hunting practices. Remember to consult your specific reloading manual for optimal results and always practice safe firearm handling.