A roughly machined chamber can cause which type of malfunction in a gas delayed blowback firearm?

A roughly machined chamber can lead to an extraction and unlocking malfunction in a gas delayed blowback firearm primarily due to improper casing fit and retention. When the chamber is not accurately machined, the dimensions may not allow the cartridge case to properly seat itself or may not provide the right amount of support to the casing. This can cause the extraction process to be disrupted, leading to difficulties in removing the fired cartridge case from the chamber after firing.

In a gas delayed blowback system, the timing of extraction and unlocking is critical. If the case does not expand properly within the chamber due to poor machining, it may not release from the chamber in a timely manner. As a result, the action may begin to unlock prematurely, causing the bolt to attempt to extract the spent casing while it is still partially engaged in the chamber. This situation can lead to jams or failures to extract as the system struggles to cycle.

Maintaining precise machining tolerances in the chamber is vital to ensure that the mechanism operates smoothly and that the extraction and unlocking processes occur as designed, preventing operational failures.