The 5.56mm 55 grain M193 round has a plain tip. As the Centerfire Sporting, or .223 Remington, it first appeared in 1957 as an experimental military cartridge. In 1964, it was officially adopted by the U.S. Army as the 5.56mm Ball cartridge M193.
Manufactured at the Lake City Army Ammunition Plant (LCAAP), it has proven to be an effective military cartridge for fighting in jungle or forested areas and for close-in fire support. The cartridge was first combat-tested in Vietnam in the early 1960s. It is used in the M16, M16A1, M16A2 and M4 rifles.