I've got a post ban Colt Match Target (6601) that is very accurate.  I'm affraid if I have the barrel threaded for a flash suppressor I'll loose some accuracy.  I'm contemplating
buying a new Colt barrel assembly w/ threads and bayo lug.  The new barrel is about $450 vs. $100 for threading.  Opinions?

This was my first AR-15 so the sentimental part of me wants to keep it stock, hence the Colt barrel.

Also how hard is it to change a barrel on your own?

Don't worry about losing accuracy, threading won't have an effect on that.

It is super easy to remove your own barrel, now getting the FSB off is another story.  Sometimes it's easy, sometimes it's a huge pain in the ass.

Quoted: I've got a post ban Colt Match Target (6601) that is very accurate.  I'm affraid if I have the barrel threaded for a flash suppressor I'll loose some accuracy.  I'm contemplating buying a new Colt barrel assembly w/ threads and bayo lug.  The new barrel is about $450 vs. $100 for threading.  Opinions? This was my first AR-15 so the sentimental part of me wants to keep it stock, hence the Colt barrel. Also how hard is it to change a barrel on your own?

Changing the barrel is easy.
Here is a link… scroll down a bit, its on page #1 LINK

I have my barrels precision threaded for use with suppressors by Tornado Technologies Click Here For Link and have always had good luck.

I also hear that ADCO does a great job. Click Here For Link

As long as you go with someone that REALLY knows what they are doing you shouldn’t suffer accuracy problems.

Quoted: ... I have my barrels precision threaded for use with suppressors by Tornado Technologies Click Here For Link and have always had good luck. I also hear that ADCO does a great job. Click Here For Link As long as you go with someone that REALLY knows what they are doing you shouldn’t suffer accuracy problems.

+1 on having someone do it that has a good reputation, I believe that ADCO doesn't charge much (if anything) to take the barrel off the upper to do the threading if your not comfortable doing it.