I am considering my first AR-15 16" to be purchased in Jan.
Is it worth spending an extra $150 for a Bushmaster over an Eagle Arms?
What is the differnce between .223 and 5.56 or .223/556. Which is better?
What are  the accesories i should expect to need (or want) in the first few months?

First off welcome and Im sure the first AR you get wont be your last.I like bushmaster have 3 they have never failed due to anything but a bad Mag.Rock River is also good and Armalite.Get a chrome lined barrel more reliable and easy to clean,wont rust.The difference between .223 and 5.56 is usually related to chamber size and .223 is ussually match grade ammo.5.56 is what you want the chamber is a little more roomy and will chamber all 5.56 and .223 ball and match ammo what have you.Some thing that is .223 usualy varmint rifles or precision ARs will only take match grade .223 you cant use any military 5.56 or ammo made to those specs because the tighter chamber causes higher presures.If you choose any rifle beside the Bushmaster make sure you get a chrome lined 5.56 chamber and as far as accesories learn to use your iron sights first then worry about gadgets. when you can hit targets off hand at 50 and 100 yds then you can start shooping for an aimpoint or whatever you like.Even if you get a red dot sight now just make sure you can use your irons first.Ther are plenty of knowledgeable people here who Im sure will chime in,plenty of good advice to go around and gadgets and rifle configuration usualy coincide with what you are going to use the rifle for..competition,Field just fun home defense,where you live country? or city? list all the info you can on what your needs are and folks here can give you some good insite as to what you may want for a rifle and for your rifle when you get it. And welcome again to the site.

Welcome to the board,get the bushy you wont regret it.I have 2 bushy 16"s and love them.

Welcome to the board Coal.
As previously stated a rifle chambered in .223 has a shorter case neck length, and will have over pressure problems with 5.56 ammo.
As such a rifle chambered for 5.56 will shoot .223 but not the other way around.
For accesories, I would stick with the basic rifle at first.
Get your marksmanship skills up with it, get familiar with the weapon, then look around, and determine what you want and need.

Congrads. A few things you will need. I perfer an Otis cleaning kit.They sell for $20 -$40 according which one you get. Then some type of CLP. A bottle of Hoppe #9 is good to kill the carbon. CLP to lube and protect the rifle. Get a case of ammo from ammoman.com or ect..... You want to get only USGI mag IMO. You can start off with just 2 or 3 to get you started.They are $20-$30 a piece also normally. Like the other poster stated.Learn to hit with your IRONS. Irons won't fail you gagets can and will.Congrads again WarDawg

Thanks for the advice. I was in the National guard for 6 years and consitantly fired expert with an m16a2. That's what has inspired me to add one to my collection. I was considering an eagle for the price tag, are there any ar's for around the $750 price tag that might be better quality? I will mostly be plinking, but would certainly like accuracy at 300+ meters.

Bushmaster - Best AR avaliable

Hi Coal, and welcome. I have a Bushmaster 16" and am VERY happy with it, and i think you would be too. before taxes my price tag was 750, not bad at all for such a fine rifle! good luck!

Dagger

Welcome! [:)] You can't go wrong with the Bushmaster, as far as accessories go, you are prob. gonna want LOTS of mags and ammo, at least in the beginning, then its just gonna get worse......

I have a Pre and Post BM. My 10 yar old gun runs just as well as the new 20"A2. Ive got one Oly Preban as well, it shoots fine and runs well but Ill always be a Bushmaster fan. They are the best in my book. Good tech support when you need them, cust svc. is very good also...You cant go wrong with those guys!.... John

Welcome to the site, Coal.  Bushmaster's the best.  You'll be happy with it.  And if there is a problem they have excellent customer service and a rep right here on this site.

[8D]

Yes, but Eagles are good too

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This can be a very personal decision, as there are thousands of accessories available. Most of us end up with multiple AR's because there is so many options.

Thanks Notack, that site was very helpful. I even taught my local gun dealer a few things.
Thanks for all the help guys I'll let yall know what i get.