Mosin-Nagant Factory Pressure Test Rifle

Published on November 20, 2018
Duration: 8:33

This video details a rare Mosin-Nagant M1891 rifle specifically designed for factory pressure testing. Host Ian McCollum explains the historical method of measuring chamber pressure using copper slugs (CUP) and the specialized apparatus attached to the rifle's receiver. The rarity of such a complete testing kit is highlighted, making it a significant find at auction.

Quick Summary

A Mosin-Nagant M1891 Pressure Test Rifle is a rare firearm modified for factory ammunition testing. It utilizes a specialized apparatus on the receiver to measure chamber pressure via historical Copper Units of Pressure (CUP) method, which quantifies the deformation of a copper slug.

Chapters

  1. 00:00Introduction to Pressure Test Rifle
  2. 00:30Measuring Chamber Pressure (CUP)
  3. 01:08Pressure Testing Device Details
  4. 02:26Slug Compression Mechanism
  5. 03:37CUP vs. PSI Discussion
  6. 04:18Standard Test Firing Plug
  7. 05:25Rifle Markings and Condition
  8. 06:10Conclusion and Rarity

Frequently Asked Questions

What is a Mosin-Nagant Pressure Test Rifle?

A Mosin-Nagant Pressure Test Rifle is a rare variant of the M1891 designed specifically for factory testing. It features a unique apparatus on the receiver to measure chamber pressure during ammunition proofing using historical methods like Copper Units of Pressure (CUP).

How was chamber pressure measured historically on this rifle?

Historically, chamber pressure was measured using a method called Copper Units of Pressure (CUP). This involved a calibrated copper slug that would be compressed by the firing event, with the degree of deformation indicating the pressure level within the chamber.

Why is there no direct conversion between CUP and PSI?

There is no direct conversion factor between CUP and PSI because CUP is a secondary measurement that reflects the physical effect of pressure on a copper slug, rather than a direct reading of the pressure itself. Modern PSI measurements are more precise.

What makes this Mosin-Nagant M1891 particularly rare?

This Mosin-Nagant M1891 is rare due to its specialized function as a factory pressure test rifle and the presence of a complete, original testing apparatus. Such complete kits are seldom found, especially with matching serial numbers and historical cartouches.

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