.223 vs 5.56

[clm]

Please help a new guy,
I willl purchase a new ar soon but need some help with the differences between .223 and 5.56 ammo.
Thanks in advance!

[Hazcat]

What it comes down to is if your rifle is chambered for 556 it will shoot 223.  If your rifle is chambered for 223 it may not shoot 556.

[tew]

Most of the AR type rifles are 5.56, so they will shoot either.  I think I've heard the biggest difference are chamber pressures.

[Hazcat]

Most of the AR type rifles are 5.56, so they will shoot either.  I think I've heard the biggest difference are chamber pressures.

Yep.  According to an article in American Rifleman Sept 2007 issue that is the big reason.

[2HOW]

Here is probably the best sight for this question             http://www.ammo-oracle.com/body.htm

[Sponsor]

[clm]

Thanks for the info!
Does anyone find a brand of AR to shoot moe accurately than another, especially at 150-200 yards?
I like to photocopy paper money and shoot the portraits, is this accuracy possible at 150-200 with an AR?
Savage 12 Low Profile in .204 is no problem up to about 250 yards if there is no wind!

[gunman42782]

You might have to get a varmint/target model AR to get that kind of accuracy, but heck yes, the AR can do it.  Carl Bernosky won the High Power Rifle Championship this year with a highly modified AR. 

[Bidah]

Clm,

Here we go taking the thread off topic...

You will need to move up to a Target/DCM/Varmit rilfe as was said.  My DCM rifle will do 2" groups easy at 200m if I do my part with my match reloads.  You could possibly go cheaper, if you need to, by using a HB 20" and then getting a free float tube.  My off the shelf one built by me will do this, but it is not quite as good as the DCM one.  It will pull just over 3" at 300m, again with my match reloads.

So, you have options.  Which way do you believe that you would like to go?  Better yet, post that question as it's own thread so we have it for reference later...

--------- back to thread ------------

Yes, 5.56 has higher pressures.  I also believe that the .223 is a tighter chamber.  Don't quote me though 

-Bidah

[2HOW]

Ammo has a lot to do with accuracy along with twist. The boat tails seem to be more accurate, but the steel core seem to be less . check with ammo oracle on this.

[BULLDOG]

Rock River Arms AR's shoot very tight groups right out of the box.  "if it ain't broke, don't fix it"