IMR 4064 is a popular propellant choice among reloaders for the .308 Winchester cartridge, particularly with 150-grain bullets. Its versatility and consistent performance make it a reliable option for various applications, from hunting to target shooting. However, understanding its characteristics and nuances is crucial for safe and accurate reloading. This guide delves into the specifics of using IMR 4064 with 150-grain bullets in the .308 Winchester.
Understanding IMR 4064
IMR 4064 is a medium-burning, extruded powder known for its relatively low pressure and excellent metering characteristics. This makes it a favorite for both beginners and experienced reloaders. Its moderate burn rate is well-suited to a wide range of bullet weights and case capacities, contributing to its popularity in the .308 Winchester. However, its performance is sensitive to variations in temperature and charge weight.
IMR 4064 and 150-Grain Bullets: Load Data Considerations
Disclaimer: This information is for educational purposes only. Always consult your reloading manuals and manufacturer's data sheets for safe and accurate load data before attempting to reload ammunition. Never exceed maximum recommended loads. Improper reloading practices can result in serious injury or death.
While IMR 4064 works well with 150-grain bullets in the .308 Winchester, the specific load data will depend on several factors including:
- Bullet type: Different bullet manufacturers produce 150-grain bullets with varying ballistic coefficients, jacket thicknesses, and overall lengths. These variations will impact the optimal powder charge.
- Case manufacturer: Case capacity can vary slightly between manufacturers, necessitating adjustments in powder charge to maintain safe pressure levels.
- Primer type: The type of primer used can influence ignition and overall pressure. Small variations in primer performance can necessitate minor adjustments in powder charge.
- Rifle characteristics: The barrel length, twist rate, and chamber dimensions of your specific rifle will influence the accuracy and velocity of your loads.
It is crucial to start with the minimum recommended charge from a reputable reloading manual and work up gradually, carefully monitoring pressure signs. Pressure signs can include excessive primer flattening, sticky bolt lift, or unusual noise. If you observe any pressure signs, immediately stop increasing the powder charge and consult your reloading manual.
Finding Reliable Load Data
Several sources offer reliable load data for IMR 4064 and 150-grain bullets in .308 Winchester:
- Hodgdon Powder Company: The manufacturer's website provides comprehensive data, often including velocity and pressure information.
- Reloading manuals: Books like those published by Lyman, Sierra, Hornady, and Lee Precision contain extensive data tables compiled from rigorous testing.
- Online reloading forums: Experienced reloaders often share their data, but always verify information with multiple sources and use caution.
Optimizing Your Loads
Once you have established a safe starting load, you can experiment with minor adjustments to fine-tune your accuracy. Factors to consider include:
- Powder charge: Small increments of powder can significantly impact velocity and accuracy. Keep meticulous records of your tests.
- Collet Seating Depth: This affects the overall bullet seating depth and can influence accuracy.
- OAL (Overall Cartridge Length): Ensuring your OAL is within the safe limits for your rifle is essential to prevent problems with feeding and chambering.
Conclusion
IMR 4064 offers a reliable and versatile powder choice for 150-grain bullets in .308 Winchester. However, safe and accurate reloading necessitates careful attention to detail, adherence to established load data, and responsible reloading practices. Always prioritize safety and consult reputable sources for accurate information before attempting to reload ammunition. Remember to always double-check your work and never take shortcuts when it comes to reloading.
