Color-tipped ammunition is produced by various ammunition manufacturers and, unfortunately, the colors are not necessarily universal. Manufacturers may also use colored tips to represent a certain bullet type or style, tracer indicator or jacket type.
Green-tip ammunition is most common in 5.56/.223 Rem caliber and is mainly designed for use with the AR platform. These rounds were originally considered controversial, as they meet one of the criteria of the federal definition of armor-piercing ammunition. However, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) has exempted 5.56/.223 Rem ammunition, clarifying that it is legal to purchase, possess and use.