Is .223 the same as 5.56?

Question

is .223 the same as 5.56?

Answer 1

Yes it is

Answer 2

No they are slightly different.

Military specification chamber and throat dimensions for (5.56X45 NATO)firearms have slightly different dimensions in the chamber and throat as compared to the civilian, SAAMI specification .223 Remington chambers. Also the NATO specification brass case has slightly less internal volume than the commercial .223 Remington brass case.

For guidance, SAAMI recommended in 1979 that 5.56X45 NATO military ammunition not be fired in commercial .223 Remington sporting rifles, due to the possibility of excessive chamber pressures resulting from the chamber and throat differences.

As far as firing commercial .223 Remington ammunition in a firearm

stamped 5.56 NATO, there is no problem. However, when reloading

military brass, reduced loads are recommended due to the reduced

internal volume of military cases as compared to commercial cases.

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Answer 3

they are very close but you would have to know what to look for to tell the difference

Answer 4

not exactely.  but most rifles that can fire one, can fire the other.

Answer 5

you can fire .223 in a gun chambered for 5.56 but not the other way.

Answer 6

a 5.56 will not chamber into a .223...

Answer 7

same diameter.  there are some differences.  

read to your heart's content here

http://en.wikipedia.org/wiki/.223_Reming...