The most powerful legal firecracker is the M-80. It was first developed by the U.S. military in the early 1950s for use as a signal device and later became available to the public in the 1960s. The M-80 is classified as a Class C explosive by the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), meaning it is powerful enough to cause property damage or personal injury if used improperly.
While M-80s are no longer manufactured in the United States, they can still be legally purchased from some fireworks retailers. However, many states have banned or restricted their sale and use due to safety concerns. In addition, possession of an M-80 without a permit is illegal in some jurisdictions.
Despite their potential danger, M-80s are popular among fireworks enthusiasts due to their loud bang and bright flash when detonated. When used properly, they can provide a spectacular show for spectators while posing minimal risk to those nearby.