WILSON 6MM GT CASE LENGTH HEADSPACE GAUGE

The L.E. Wilson Case Gage is a one-piece precision tool designed to check both case length and headspace in fired cases. Available for most popular rimless cases. The Cartridge Case Gage was designed with safety in mind and was invented by our founder Sam (L.E.) Wilson in 1935 after a fellow shooter approached him for help in solving a case-separation issue. This case gage allows you to see just how much you are sizing back your shoulder on your cases.

How to Use It

1. Measure a case in AS-FIRED condition. Note the headspace measurement.
2. Resize your case on the current die setting.
3. Place the resized case back into the gage.
4. Use a Case Gage Depth Micrometer to see how much you are sizing the shoulder back.
5. Adjust your sizing die to achieve your desired shoulder set back.
6. Recheck the case length—trim if case exceeds max length step.

Why It’s Essential

• Prevent over-sizing and case separation
• Know exactly when brass needs trimming
• Gain consistency in chamber fit and pressure control
• Ideal for bolt action and precision shooters

Note: Does not measure body diameters. This gage is intended to be used with fired cases to determine a basis for full length sizing and trimming.