Brownells - Case Sizing: Part 1 - Why We Full Length Resize

Published on August 23, 2012
Duration: 2:34

This video explains the fundamental reasons behind full-length case resizing in reloading. It details how fired brass expands and stretches, necessitating resizing for reliable chambering and proper bullet retention. The guide outlines the functions of a full-length sizing die and introduces three methods for its setup, emphasizing the importance of correct headspace adjustment.

Quick Summary

Full-length resizing is essential in reloading because fired brass expands under pressure, filling the chamber. Without resizing, cases may be too tight to chamber, and the neck may not grip the bullet properly. A full-length die sizes the case body, neck, removes the primer, and critically adjusts headspace for reliable function.

Chapters

  1. 00:00Introduction to Reloading Room & Case Sizing Questions
  2. 00:12Why We Full Length Resize Cases
  3. 00:15Case Expansion Under Pressure
  4. 00:32Consequences of Not Resizing
  5. 00:43Functions of the Full Length Die
  6. 01:00Importance of Headspace Adjustment
  7. 01:14Setting Up the Full Length Sizing Die
  8. 01:22Three Basic Die Setup Methods
  9. 01:24Method 1: Manufacturer's Directions
  10. 01:43Method 2: Using a Headspace Gauge
  11. 01:47Example: 30-06 Springfield Cases
  12. 01:58Method 3: Setting Up By Feel (Not Recommended)
  13. 02:19Preview of Part 2: Manufacturer's Directions Setup

Frequently Asked Questions

Why is full-length resizing essential for reloading ammunition?

Full-length resizing is crucial because fired brass expands significantly under chamber pressure. Without resizing, cases may become too tight to chamber reliably, and the neck may not hold a bullet securely, impacting accuracy and safety.

What are the primary functions of a full-length sizing die in reloading?

A full-length sizing die sizes the case body for chamber clearance, sizes the neck for proper bullet grip using an expander ball, removes the spent primer, and critically, adjusts the cartridge's headspace for reliable function.

How is headspace defined in the context of reloading and firearms?

Headspace is defined as the allowable forward and backward movement of a cartridge case within the firearm's chamber when the firearm is discharged. Proper headspace is vital for safe and reliable operation.

What are the recommended methods for setting up a full-length sizing die?

The recommended methods for setting up a full-length sizing die include following the manufacturer's directions or using a specific headspace gauge for the cartridge. Setting up by feel is generally not advised due to its subjective nature.

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