556 - 223 = 333
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.
No. They have matching dimensions, but differ in other areas, such as neck angles. .223 ammunition can be safely fired in a 5.56x45mm chamber; 5.56x45 ammunition is not recommended to be used in a .223 Remington chamber.
.223 Remington can be cycled in a 5.56x45 rifle; 5.56x45 should not be cycled in a .223 Remington firearm.
Yes it does, unless your barrel is stamped .223 .
if it is a 223 cal, then yes
yes, except 556 is written as 5.56 caliber (223) Actually, no, it isn't. Although the dimensions match, the military 5.56 cartridge differs from the civilian .223 in several aspects, such as the neck angle, casing thickness, and chamber pressure. A general rule of thumb is that .223 Remington can be fired in a 5.56 chamber, but 5.56 ammo should not be fired in a dedicated .223 chamber.
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.
lighter bullet and more ammo can be carried as opposed to the 30/06 or 308
I assume that you are referring to 5.56mm in your question?,if so yes you can shoot this ammo in your rifle.The 5.56mm is the metric designation for the .223 Remington cartridge.
No But the Caliber is the same but theres more powder in the 223
Yes the mags work with both ammos. You can not tell the difference in the two by looking at them.