What is the minimum duration since the last determination for a barrel to be considered hot in the M2A1?

The correct duration for a barrel to be considered hot in the M2A1 is indeed 15 minutes. This period is based on the cooling characteristics of the barrel material and the heat generated during firing. After extensive use, such as sustained firing drills, the barrel reaches temperatures that can affect both performance and safety.

The 15-minute duration provides a standard timeframe during which the heat dissipates enough to allow operators to assess if the barrel can be safely handled or if further cooling is required. This cooldown period is crucial for maintaining the integrity of the barrel and ensuring optimal performance during subsequent use. Recognizing the importance of this timeframe helps operators manage weapon safety effectively, avoiding risks associated with handling an overheated barrel.