What does it mean when you hear a quiet sound similar to that of the is heard grenade goes off near you?

If you hear a quiet sound similar to that of a grenade going off near you, it could be a dud grenade, also known as a dud round. A dud round is a piece of ammunition that fails to explode after being fired. It can still be dangerous, as it may still contain live explosives and could detonate if disturbed or handled improperly. If you come across a dud round, it is important to remain calm and not move or touch it. You should immediately report the location of the dud round to the local authorities or emergency services. They will be able to safely dispose of the dud round and ensure that there is no danger to the public.