What round is used for training to simulate live fire?

The M200 round is specifically designed for training purposes and is used to simulate live fire without the associated dangers. It is a blank round that replicates the sound and recoil of a live round but does not have a projectile, making it safe for training scenarios. This allows service members to develop their skills in handling weapons and practicing drills without the risks associated with live ammunition.

In training environments, using the M200 helps maintain realism while ensuring safety for all participants. This is crucial for familiarizing personnel with weapon handling, discharge protocols, and response tactics effectively. Other options listed, like the M855 and M240, are live ammunition or specific weapon systems not intended for training without live fire. Hence, the M200 stands out as the correct choice for simulated live-fire training.