How many rounds of blank or ball ammunition must be fired after replacing the bolt carrier key to ensure a seal is created?

Firing 3 to 8 rounds of blank or ball ammunition after replacing the bolt carrier key is essential to ensure that a proper gas seal is formed within the firearm. This process is necessary because the sealing mechanism relies on the components settling into their operational positions and creating a tight seal to prevent gas leakage. The specified number of rounds is based on the functional characteristics of the weapon, which allows the parts to wear into position while also establishing the necessary pressures to ensure operational reliability.

The specified range allows for variances in individual weapon conditions and tolerances, ensuring that enough rounds are fired to achieve the desired outcome. If too few rounds are fired, there may still be an inadequate seal, which can lead to malfunctions. Conversely, firing more than needed might be wasteful and unnecessarily prolong the process. Thus, the recommendation to fire between 3 to 8 rounds strikes a balance between efficiency and effectiveness in achieving a reliable seal.