Yeah, the round is 5.56 mm idiot. If its 556mm, you convert from millimetres to centimetres it's 55.6 cm, then to metres it would be 0.556 m, so again, that's not a rifle round, that's a long range artillery shell.
Mate you're the hollow skulled bottom boy that's saying you'll kill someone with a artillery cannon from point blank range, has your ass even had a thought ever?
Calling yourself a giant is like calling yourself a 556mm round,you are large yes,but there will be an asshole who will correct you stating that it does not exist
Oh no! Someone's saying I'm striving to be the best I can be! What ever shall I do?! Mate honestly just stfu, and for once in your life, actually do something right.