What does the RPG-7 expansion chamber ensure?

The RPG-7's expansion chamber plays a critical role in the weapon's functionality by ensuring that the launch tube does not fail under the intense stress generated by expanding gases during firing. When a round is fired, the combustion of the propellant creates high-pressure gases that rapidly expand. The design of the expansion chamber allows these gases to expand in a controlled manner, reducing the pressure exerted on the walls of the launch tube. This is crucial for maintaining the structural integrity of the tube and ensuring the safe and reliable operation of the weapon. Without this design feature, the launch tube could experience catastrophic failure, posing a danger to the user and compromising the effectiveness of the RPG-7.

In contrast, balancing during firing, achieving longer distances, or managing the temperature of the launch tube are not directly related to the specific function of the expansion chamber.