Zastava M90 OUT of GAS!

Published on December 19, 2021
Duration: 22:00

This guide details the 'Sand Tornado Test' performed on the Zastava M90, highlighting its adjustable gas system and potential failure points. Expert analysis from Rob Ski of AK Operators Union identifies a critical issue with the gas regulator retainer bracket losing tension under recoil, leading to malfunctions. The guide provides steps for field diagnosis, temporary adjustment, and a permanent corrective action to ensure reliable operation in adverse conditions.

Quick Summary

The Zastava M90 experienced a critical failure where its adjustable gas regulator ring lost tension and shifted position during a 'Sand Tornado Test.' This issue, stemming from the gas regulator retainer bracket, prevents proper cycling. A fix involves removing the gas tube and manually bending the bracket to increase tension, ensuring reliable operation in adverse conditions.

Chapters

  1. 00:00Sand Tornado Test Introduction
  2. 01:25Test Execution and Initial Malfunction
  3. 02:41Internal Inspection and Sand Ingress
  4. 06:04Identifying the Gas Block Failure
  5. 11:11Field Adjustment Issues
  6. 13:31Final Diagnosis and Corrective Action

Frequently Asked Questions

What is the primary failure mode observed with the Zastava M90's gas system during adverse condition testing?

The primary failure observed is the gas regulator ring moving out of its locked position due to insufficient tension from the retainer bracket. This causes the gas system to malfunction, leading to cycling issues and stoppages.

How can the gas regulator retainer bracket tension be increased on a Zastava M90?

To permanently fix low tension, remove the gas tube and manually bend the gas regulator retainer bracket. This increases its tension, ensuring it securely holds the gas ring in the desired setting under recoil.

What is the 'Sand Tornado Test' and why is it relevant for the Zastava M90?

The 'Sand Tornado Test' involves subjecting a firearm to heavy sand ingress during rapid fire to simulate extreme adverse conditions. It's relevant for the Zastava M90 to assess the reliability and durability of its gas system and overall operation under stress.

What are the key technical specifications of the Zastava M90 discussed?

The Zastava M90 features a 1.5mm bulged trunnion receiver, an 18.25-inch barrel, and a 3-position adjustable gas system. It is chambered in 5.56x45mm NATO.

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