300 Blk Sizing Die Shootout - Part 1

Published on September 10, 2017
Duration: 58:29

This guide details a comparative analysis of Forster, Lee Precision, and RCBS sizing dies for 300 Blackout ammunition, as presented by Johnny of Johnny's Reloading Bench. The expert-level instruction focuses on identifying dies that provide optimal neck tension and prevent bullet setback, crucial for both accuracy and feeding reliability. The process involves meticulous measurement of expander balls, case stretch, and headspace, followed by live-fire testing to evaluate accuracy and velocity.

Quick Summary

Johnny's Reloading Bench compares Forster, Lee Precision, and RCBS 300 Blackout sizing dies, finding Forster and RCBS produced tighter groups and resisted bullet setback better than Lee. Key factors analyzed include expander ball diameter, neck tension, and shoulder bump, highlighting the importance of die selection for reliable ammunition.

Chapters

  1. 00:00Introduction to 300 Blk Sizing Die Shootout
  2. 01:34Background on Accuracy and Feeding Issues
  3. 03:09Test Methodology and Load Data
  4. 06:20Die Inspection and Expander Ball Measurements
  5. 13:55Sizing and Post-Sizing Measurements
  6. 18:12Loading and Range Testing
  7. 21:11Results: Bullet Setback and Accuracy
  8. 24:38300 Blackout PMAG Comparison

Frequently Asked Questions

What are the key factors to consider when choosing a 300 Blackout sizing die?

Key factors include the expander ball diameter for neck tension, the die's design for shoulder bump, and its overall impact on case stretch and bullet setback. Forster and RCBS dies often provide superior neck tension and accuracy compared to standard Lee dies for 300 Blackout.

How does bullet setback affect 300 Blackout ammunition?

Bullet setback occurs when the bullet is pushed deeper into the case during chambering, reducing case volume and potentially increasing chamber pressure. This can lead to inconsistent ignition and reduced accuracy, and in extreme cases, over-pressurization.

Which 300 Blackout sizing dies performed best in the shootout?

In this specific test, the Forster and RCBS sizing dies demonstrated better performance regarding accuracy and resistance to bullet setback when compared to the Lee sizing die, especially when used with Lake City brass.

Why is neck tension important for 300 Blackout reloads?

Sufficient neck tension is crucial for holding the bullet securely in place, preventing it from moving deeper into the case (bullet setback) during feeding and firing. This consistency is vital for reliable feeding and accurate shot placement.

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