The 5.56x45 cartridge is dimensionally similar to a .223 Remington. However, the two are not the same. A 5.56 chamber can safely fire .223 rounds, but a dedicated .223 chamber can't necessarily fire 5.56 cartridges safely, given the different angle of the cartridge neck, and the higher chamber pressures generated by the 5.56 cartridge over the commercial .223 round.
5.56 hands down.
556
556 * 556 = 309,136
556 = 55,600%
Yes there is a difference. They are physically the same size casing, but the 556 military rounds' chamber pressure is ~10,000 psi higher then 223. Military rifles generally have chambers with a different throat configuration than normal sport 223 rifles. This being said, I would not recommend shooting 556 unless your rifle was designed for the higher pressures.
why you asking me 556-thousands = 556/1000 = 0.556 as a decimal
70% of 556 is 389.2. Which means that 166.8 is 30% of 556.
556
It is: 556 = DLVI
563 + 556 = 1019
556 x 2 = 1,112
556 - 223 = 333