If your MK19 machine gun won't shoot, what is the first step you should take?

The first step to take when an MK19 machine gun won't shoot is to clear the weapon. This step is crucial because it ensures that the weapon is safe before conducting any further troubleshooting. Clearing the weapon eliminates the possibility of an accidental discharge while inspecting or trying to identify the issue causing it not to fire.

After clearing the weapon, the next logical steps would involve performing a function check, checking the ammunition, and inspecting the barrel. Each of these actions addresses specific potential problems. However, clearing the weapon is foundational and necessary to maintain safety during the troubleshooting process.