5.56 and .223 the same round?

[scudd1999]

Ok guys...or gals....I am a rookie re loader messing around with my new bushmaster and what I need to know is the 5.56 and .223 the same round? I have heard arguments saying yes and no. I do know that some reloading info differs in information such as the holding dies made by Lee gives 2 different sizes. One for .223 and 5.56. I know my Bushmaster will shoot both marked rounds but I have seen stamped out AR's saying .223 only. What gives?

Another issue: Reloaded some .223 Sierra MatchKing 53 GR with a 27 grain load (max is 27.5) with hodgdon Varget powder. I Can honestly say there was a marked improvement on accuracy @ 100 and 200 meters over the Federal 5.56 (55 grain) factory. Question is.....obviously the lighter rounds seem to be more accurate...maybe because of quality/powder/reloading bullet more evenly.....probably lots of reasons. Do I have to sacrifice my accuracy for the heavier hunting rounds I want to load? Can anyone suggest a good hard hitting hunting round with a powder load that gives great accuracy?
Thanks,
Jeff

[FormerUser123]

5.56 is a higher pressure round than .223. Exterior dimensions are identical, but the extra pressures in 5.56 may damage a .223 only chamber. .223 Wylde and 5.56 chambered barrels can shoot both.

[Connal]

Not the same. Here is a visual aid to assist.

[jtwalker]

Agree with Connal.

And I've read that you can fire either from a barrel stamped 5.56, but only .223 from a barrel stamped .223.

[SharpShooter88]

Holy crap another 5.56 V .223 thread....Read around....there are tons of these threads....


Not the same round. Different case pressures and such.