RN 50 Caliber Change

Published on September 23, 2022
Duration: 5:43

This guide details the process of converting a Mark Serbu RN 50 rifle from .50 BMG to 6.5x55 Swedish caliber. It involves machining a custom adapter bushing and installing a new barrel compatible with Savage 10/110 series actions. The process is explained by Mark Serbu, a recognized gun designer, highlighting the technical steps and considerations for such a modification.

Quick Summary

Converting the RN 50 rifle involves a custom adapter bushing that threads into the receiver, allowing for the installation of a new barrel. This method, detailed by gun designer Mark Serbu, facilitates caliber changes like .50 BMG to 6.5x55 Swedish, often to bypass export regulations and manage recoil.

Chapters

  1. 00:00Introduction & Purpose
  2. 00:29Motivation for Caliber Change
  3. 00:46Previous Conversions & Backlog
  4. 01:05Conversion Method Explained
  5. 01:23Acquiring the 6.5x55 Barrel
  6. 01:44Barrel Features & Finish
  7. 02:16Ammunition Anecdote
  8. 02:53Machining the Adapter Bushing
  9. 03:15Bushing Thread Specifications
  10. 03:40Test Firing & Results
  11. 04:57Firing Pin & Conclusion

Frequently Asked Questions

How is the RN 50 rifle converted to a different caliber like 6.5x55 Swedish?

The conversion involves a custom-machined adapter bushing. This bushing threads into the RN 50 receiver, and a new barrel, threaded to match the bushing, is then installed. This method allows for caliber changes without altering the core receiver design.

What are the key specifications for the adapter bushing in an RN 50 caliber conversion?

The adapter bushing requires external threading (1.5-12) to match the RN 50 barrel interface and internal threading (1-1/16-20) to accept a barrel compatible with Savage 10/110 series actions.

Why would someone convert an RN 50 from .50 BMG to 6.5x55 Swedish?

A primary reason is to overcome export restrictions, as .50 BMG is heavily regulated internationally. Additionally, 6.5x55 Swedish offers a more manageable recoil and is readily available, making it a practical alternative for certain applications.

What type of barrel is suitable for a 6.5x55 Swedish conversion on the RN 50?

A 26-inch varmint barrel with a 1:8 twist rate, designed for Savage 10/110 series actions, is suitable. It should also feature an 11-degree target crown for optimal accuracy.

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