What is the Bump on Older Revolvers? What Does It Do? Why is It Not There Anymore?

Published on March 29, 2026
Duration: 5:12

This video explains the 'bump' or 'lug' found on older revolvers, identifying it as a frame or cylinder lug. Its primary function is to prevent the cylinder from falling off the ejector rod when opened. The video details how these lugs can be integrated into the frame, pinned, or part of the side plate, and contrasts this with modern revolvers that utilize internal mechanisms with ball bearings for cylinder retention, making the external lug obsolete. The presenter notes that while older methods required hand-fitting, newer designs are easier to manufacture.

Quick Summary

The 'bump' on older revolvers is known as a frame lug or cylinder lug. Its main purpose is to prevent the cylinder from detaching from the ejector rod when the cylinder is opened. Modern revolvers often omit this external feature, relying instead on internal mechanisms for cylinder retention.

Chapters

  1. 00:00Introduction: The Revolver Bump
  2. 00:55What is the Bump Called?
  3. 01:11Different Types of Lugs
  4. 01:38The Primary Function: Cylinder Retention
  5. 01:56Why it Was Necessary in Older Guns
  6. 02:12Modern Revolvers and the Absence of Lugs
  7. 02:45Modern Internal Retention Mechanisms
  8. 03:28Which System is Better? Manufacturing vs. Design
  9. 04:00Conclusion: Preference vs. Functionality

Frequently Asked Questions

What is the bump on older revolvers called and what does it do?

The bump on older revolvers is commonly called a frame lug or cylinder lug. Its primary function is to act as a physical stop, preventing the cylinder from falling off the ejector rod when the cylinder is swung open.

Why are these bumps not found on many newer revolvers?

Newer revolvers often utilize internal retention mechanisms, such as ball bearings within the ejector rod assembly, to hold the cylinder in place. This makes the external lug obsolete and simplifies the manufacturing process.

How were these frame lugs on older revolvers implemented?

Frame lugs could be integrated as part of the side plate, pinned into a hole in the frame, or even built directly into the frame itself. Older designs often required hand-fitting by a gunsmith.

What is the advantage of modern internal cylinder retention systems?

Modern internal retention systems are easier to manufacture as they don't require individual hand-fitting. This leads to a more streamlined production process and potentially lower costs for consumers.

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