Quick Answer
For 7mm SAUM, the best load development process involves shooting a chronograph, using a consistent 5-shot group target, and developing loads using a step-by-step approach with incremental powder charge increases. Start with a reliable starting point, such as a proven load from the manufacturer's recommendations, and incrementally increase powder charge while measuring velocity and group size.
Choosing the Right Starting Point
When developing a new load for 7mm SAUM, it’s essential to start with a reliable starting point. This can be a load from the manufacturer’s recommendations or a well-known, proven load in the 7mm SAUM cartridge. For example, a starting point could be the Hodgdon VARGET 65.5 grains with a 140-grain bullet. This load has a known trajectory and expansion characteristics, making it an excellent starting point for load development.
Measuring Velocity and Group Size
To effectively develop a load, it’s crucial to measure both velocity and group size. Use a chronograph to measure velocity, and a 5-shot group target to measure group size. Incrementally increase the powder charge in small steps (0.1-0.2 grains) while measuring velocity and group size. This step-by-step approach allows you to monitor the effects of changing the powder charge on both velocity and group size.
Load Development with a Focus on Velocity and Expansion
When developing a load, focus on achieving the desired velocity range (approximately 2,800-3,000 FPS for 7mm SAUM) while maintaining a consistent expansion profile. Use a ballistic calculator to determine the optimal velocity range for your specific hunting application. Measure the expansion characteristics of the bullet by firing the developed load at a ballistic gel block or other suitable medium, and verify that the bullet expands as expected. This approach ensures that your developed load performs as intended in the field.
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