What does the 5.56 in a 5.56x45 mm bullet mean? Is it the caliber
Steve Johnson - 69/205 - The Firearm BlogThe Firearm Blog
File:5-56 5-45 mm cases.jpg - Wikipedia
Is there an AK that can shoot 5.56X45mm? - Quora
NATO cartridge - Wikiwand
7.5×55mm Swiss - Wikiwand
5.56 45mm NATO
Steve Johnson - 69/205 - The Firearm BlogThe Firearm Blog
7.92×57mm Mauser - Wikipedia
556xi, Rainbow Six Wiki