What is the first step in disassembling the bolt carrier group of an M16A2 rifle?

The first step in disassembling the bolt carrier group of an M16A2 rifle is the removal of the firing pin retaining pin. This step is crucial because the firing pin retaining pin secures the firing pin within the bolt carrier group. By removing this pin first, you can then safely take out the firing pin, which is essential for subsequent disassembly steps.

Successfully removing the firing pin retaining pin allows you to proceed with disassembling the bolt assembly safely, ensuring that all components can be accessed and that the entire process is performed in the correct sequence. This logical step-wise approach is vital for maintaining the integrity of the weapon and ensuring safe practices during disassembly. Other options involve steps that would not be logically performed until the firing pin has been removed.