A firearm having a barrel and a whistle, wherein when the firearm is discharged air is forced through the whistle to cause a whistle sound. In one particular embodiment, the whistle comprises a barrel port, a channel, and a whistle port and wherein when the firearm is discharged a bullet traveling down the barrel forces air through the barrel port, the channel, and the whistle port to cause a whistle sound. In another embodiment, the whistle is associated with a firearm attachment and the firearm attachment is removably couplable to the firearm. In a further embodiment, the whistle is modifiable and modification of the whistle is configurable to eliminate or change the whistle sound. In a further embodiment, the whistle sound is associated with a signal that is transmitted to another device or central location for analysis, wherein the signal comprises a firearm identification or locational information.