The National Shooting Sports Foundation and the Sporting Arms and Ammunition Manufacturer’s Institute (SAAMI) have produced a video for firefighters about the impact of fire on stored ammunition. This video and the tests they performed serves to dispel many of the myths about stored ammunition. It is actually rather interesting and I would recommend you share it with any friends that are either paid or volunteer firefighters.
The bottom line is that while it makes a lot of noise when it is “cooking off”, ammunition poses little risk of injury to fire fighters or neighbors. When they burned up over 28,000 rounds of ammo in a bonfire, very few of the projectiles even penetrated one layer of sheetrock and none penetrated the second layer. A firefighter who near the fire in full turn-out gear could feel the projectiles hitting his coat but none penetrated it nor did they cause any pain.