I currently have a 16" RRA upper (HBAR) with an unthreaded muzzle.  I am considering changing this barrel out for a lightweight or M-4 14.5" barrel and having a Phantom permanently attached.  I can have Adco thread my current barrel and attach the Phantom, but how hard is it to just buy a new barrel and change it out?  Do I need to buy a new bolt carrier and bolt as well, or just a bolt?  Can I just install the new barrel and have it ready to shoot, or does it need headspaced, etc.?  

Quoted: I currently have a 16" RRA upper (HBAR) with an unthreaded muzzle.  I am considering changing this barrel out for a lightweight or M-4 14.5" barrel and having a Phantom permanently attached.  I can have Adco thread my current barrel and attach the Phantom, but how hard is it to just buy a new barrel and change it out?You will need Barrel wrench and possibly an Upper Block (it holds the upper in place without tearing anything up) youll need a ROLL PIN Punch to get roll pin outa gas tube   Do I need to buy a new bolt carrier and bolt as well, or just a bolt?Honestly , this could go either way, how many rounds are on your present BOLT? ARe planning to jus get rid of your Postban barrel? If so you are gettin rid of barrel and jus using M4 barrel and you dont have many rounds (under 200) on your present bolt, I wouldnt get a new one  Can I just install the new barrel and have it ready to shoot, or does it need headspaced, etc.?99% of all barrels, unless you specify, will come with Barrel extension attached and already headspaced.

I have about 600 rounds through my present barrel.  I would plan on just using the new barrel and getting rid of the old one.  Would I need to buy a whole new carrier group, or just a new bolt head?  I would think just a new bolt head, but want to make sure.

From what you are saying, it sounds like I wouldn't need to do any headspacing, correct?  I just want to make sure what I'm doing is safe and isn't going to result in any issues.

How much does a barrel wrench run, and are there any step by step instructions on-line for changing out a barrel?  I did assemble this AR from a lower, lower parts kit, and complete uppper, so I am somewhat mechanically inclined.  If this is a fairly easy "do it yourself" process, I think it's something I'd like to do.  However, if it's an issue of needing to headspace, etc. to ensure safe function, I will probably stay away from trying this on my own.

Thank you!

Quoted: I have about 600 rounds through my present barrel.  I would plan on just using the new barrel and getting rid of the old one.  Would I need to buy a whole new carrier group, or just a new bolt head?  I would think just a new bolt head, but want to make sure. From what you are saying, it sounds like I wouldn't need to do any headspacing, correct?  I just want to make sure what I'm doing is safe and isn't going to result in any issues. How much does a barrel wrench run, and are there any step by step instructions on-line for changing out a barrel?  I did assemble this AR from a lower, lower parts kit, and complete uppper, so I am somewhat mechanically inclined.  If this is a fairly easy "do it yourself" process, I think it's something I'd like to do.  However, if it's an issue of needing to headspace, etc. to ensure safe function, I will probably stay away from trying this on my own. Thank you!

With 600rds, thru your present bolt, I would get a new one jus to be safe. Sell your old barrel and Bolt as a unit since theyve kinda been meshed. You dont need to get a new carrier.

Get the FULL length Barrel wrench from DPMS, dont get the little cheapo one that uses a socket, those are more trouble than they are worth.

As far as instructions, there may be some on here, I would try and type them up but it is hard to explain certain steps. lol.

get the DPMS Armours Wrench, a good action block ( M&A Parts,Bushmaster etc.) a good pair of snap-ring pliers (Med. size) and a good bench Vise... took me about a half hour. super easy....

All you ever needed to know, is pinned to the top of this forum:

www.ar15.com/forums/topic.html?b=3&f=4&t=202467

Thanks!  That answers my questions!