Finding accurate and reliable reloading data is crucial for safe and successful reloading. This guide focuses specifically on .308 Winchester loads using 150-grain bullets, emphasizing the importance of precision and safety. Always consult your reloading manual and follow its instructions meticulously. This information is for educational purposes only and should not be considered a substitute for professional reloading guidance.
Understanding the Importance of Accurate Load Data
Improperly loaded ammunition can lead to catastrophic equipment failure, injury, or even death. Variations in powder charge, bullet seating depth, and overall cartridge length can significantly impact pressure and accuracy. Using inaccurate data can result in dangerously high pressures exceeding the firearm's design limits.
Key Factors Affecting .308 Winchester 150 Grain Loads
Several factors influence the optimal load data for your specific setup. These include:
- Powder Type: Different powders burn at different rates, influencing pressure and velocity. Popular powders for 150-grain .308 Winchester loads include IMR 4064, Varget, and RL15, but many others are suitable. Each powder requires its own specific load data.
- Bullet Type: The bullet's construction (jacketed, hollow point, etc.), weight, and overall design affect the pressure and accuracy. A 150-grain bullet from one manufacturer might behave differently than another.
- Case Brand and Condition: Variations in case dimensions due to manufacturer differences or previous firings can impact pressure. Uniform cases are essential for consistent results.
- Primer Type: The primer type can influence ignition consistency, which indirectly affects pressure.
- Rifle Characteristics: The barrel's twist rate, length, and chamber dimensions will affect accuracy and pressure.
Sourcing Reliable Load Data
Your primary source of load data should always be a reputable reloading manual from a trusted manufacturer. These manuals undergo rigorous testing to ensure safe and accurate data. Never rely on data found on forums or websites unless it's explicitly sourced from a verified manual.
Several well-regarded manufacturers publish reloading manuals:
- Hodgdon Powder Company
- Alliant Powder
- Accurate Powder
- Sierra Bullets
These manuals provide extensive data, including various powder types, bullet weights, and primers. They also specify safe load ranges, indicating minimum and maximum powder charges. Always start at the minimum charge listed and work your way up gradually, carefully observing pressure signs.
Interpreting Load Data
A typical load data entry might look like this:
- Powder: IMR 4064
- Bullet: 150-grain Sierra GameKing
- Primer: CCI BR-2
- Charge Weight: 42.0 grains
- COL: 2.810 inches
- Velocity: 2650 fps (approximate)
- Pressure: 55,000 PSI (approximate)
COL refers to Cartridge Overall Length. This measurement is crucial and must be precise. Slight variations can significantly affect pressure. Always measure your cartridges carefully using a case gauge.
Safety Precautions
- Never exceed the maximum listed charge weight.
- Always wear safety glasses and hearing protection.
- Work in a clean, well-ventilated area.
- Use a reloading scale that measures accurately to 0.1 grain.
- Inspect your cases, bullets, and primers for any damage before loading.
- Always double-check your measurements and powder charges.
- Start with small batches and carefully monitor for pressure signs. These can include excessive primer flow, flattened primers, or unusually loud reports.
Conclusion
Reloading .308 Winchester ammunition with 150-grain bullets can be rewarding, but safety should always be the top priority. Diligent adherence to established load data from trusted sources and meticulous attention to detail are non-negotiable. If you have any doubts or uncertainties, seek advice from experienced reloaders before proceeding. Remember, safe reloading practices are paramount.
