I went to the gun shop after reading and getting all I could without actually touching the firearm. After the shop visit Bushmaster gladly sent me a brochure in the mail. The following are questions that I have.

1) .223/ 5.56 from the brochure they said that you can fire either of the two from a 5.56 rifle. The said that they was the same in size and shape but when you load a 223 in a 5.56 you will lose velocity due to the chamber "gap" around the .223? Is this true and what are the advantage/disadvantages of both rounds?

2) If you was to buy a use AR, what would you be looking for to make sure you got a good buy or should I just count on buying new?

3)what is the difference in muzzle breaks, compenstors, and flash suppressor?

4) I saw in the brochure that some of the rifles are CARBON, with this in mind does anyone own a "carbon" AR? What do they mean when they talk about AK type ARs?

5)Seems the "izzy" is the most common compensator, what is better in terms of performance?

6)What do you reccommend me looking at before I purchase? Did you buy your first AR brand new or used?

Thanks.
further questions coming

What's with the subject line?

Quoted: 1) .223/ 5.56 from the brochure they said that you can fire either of the two from a 5.56 rifle. The said that they was the same in size and shape but when you load a 223 in a 5.56 you will lose velocity due to the chamber "gap" around the .223? Is this true and what are the advantage/disadvantages of both rounds?   www.ammo-oracle.com 2) If you was to buy a use AR, what would you be looking for to make sure you got a good buy or should I just count on buying new?   If it's your first one adn you're not familiar with ARs then I'd either buy new or look for a seller who will stand behind used rifle you're buying. 3)what is the difference in muzzle breaks, compenstors, and flash suppressor?  muzzle breaks are when three's something wrong with the metal and it cracks open.  Muzzle BRAKES are devices that redirect some of the gas coming out the barrel to reduce the recoil.  Compensators redirect some of the gases to reduce muzzle rise.  Flash hiders reduce the amount of muzzle flash.  Many devices do more than one function. 4) I saw in the brochure that some of the rifles are CARBON, with this in mind does anyone own a "carbon" AR?  There are a few around.  They are very lightweight but the company that used to make them didn't produce good rifles.  Bushmaster bought them out and have done a lot to improve them but most people are hesitant to try them.  What do they mean when they talk about AK type ARs?   Since you're talking about Bushmaster I can only assume that you are referring to models that have the AK-style muzzle brake attached. 5)Seems the "izzy" is the most common compensator, what is better in terms of performance?  "Better" depends on what you want to use the rifle for.  If you're shooting some kind of IPSC style competitions then a compensator or brake might be a good idea.  But the AR has so little recoil that I don't see a reason to use one.  When a compensator or brake redirects teh gas they generally direct it either back or to the sides which makes the noise worse for the shooter and makes it really bad for people in teh lane next to the shooter. 6)What do you reccommend me looking at before I purchase? Did you buy your first AR brand new or used?   I reccommend more time reading on  this site.  The questions you asked have all been answered at least once since the time you registered on the site.

I'll chime in on this one-

1. I seriously doubt you can measure any significant velocity/accuracy difference between a .223 & 5.56 chamber, so get the 5.56 chamber & don't even worry about it.

2. As far as a used AR, get a brand name that was factory assembled & avoid frankenstein guns.

3. Muzzle brakes & comps are the same thing, and they reduce muzzle rise at the expense of more muzzle flash & blast. I prefer the standard flash hider, which reduces flash & are less noisy, but to each his own.

4. "Carbon" means "plastic". "AK" means the rifle has the Bushy AK74 style muzzle brake. See (3) above.

5. I can't comment on the "Izzy", but I suspect it has all the advantages & disadvantages of the other brakes out there.

6. I know these subjects are beat to death here, but you can't go wrong with a name brand rifle, with a chrome bore, & 7075 upper & lower.

I'm ready for the incoming!

Quoted: 3)what is the difference in muzzle breaks, compenstors, and flash suppressor? 4) I saw in the brochure that some of the rifles are CARBON, with this in mind does anyone own a "carbon" AR? What do they mean when they talk about AK type ARs? 6)What do you reccommend me looking at before I purchase? Did you buy your first AR brand new or used?

Here are my thoughts:

Bushmaster is a good brand, so is Rock River Arms.  Either will be fine.  Don't worry whether its called 223 or 5.56 NATO.

Buy a rifle with a flash hider.  There is so little recoil/muzzle flip to begin with.  Muzzle brakes and compensators are not allowed in NRA sanctioned competition.  This may be important to you later on, black rifle disease bites hard.  

Buy a conventional AR.  Do not buy a "carbon" AR as your first rifle.  The "carbon" actually refers to graphite fibers used as structural reinforcing fibers inside  the plastic.  Not for newbies.

Buy a new rifle for your first AR.

Buy a 20" rifle.

In summary, buy the rifle most like a service rifle: M16A2 (20" barrel, A2 flash hider, integral carry handle).

RRA Standard A2

I hope this helps.

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