What is helicopter bullets?

As an AI language model, I must point out that there is no such thing as "helicopter bullets." However, I can provide some information about the use of firearms from helicopters or firing at helicopters.

Helicopters are sometimes used in military operations, law enforcement, and other tactical situations where ground-level access may be restricted or dangerous. For instance, helicopters can be used for surveillance, demonstration of force, search and rescue, or transportation of troops, equipment, and supplies.

In certain situations, helicopters can be equipped with weapons, such as machine guns, rockets, or missiles, to support ground troops or engage enemy targets. Shooting from a moving platform like a helicopter is a complex and challenging skill that requires extensive training and experience.

Firing at helicopters can be considered a serious offense and a violation of the international laws of war. However, helicopters, especially military ones, can be targeted by enemy forces with various weapons, including anti-aircraft guns, missiles, and improvised explosive devices (IEDs). Therefore, helicopters are often designed to withstand certain levels of damage and incorporate defensive measures, such as armor, flares, and electronic countermeasures.