When i bought my first ar15 it was because my local dealer had one on sale for below cost. It was a Bushmaster 20" xm15e2s a3 with a stainless steal hbar. At the time i didnt really know anything i thought all barrels where the same. It wasnt until i bought a m4 profile bushmaster that i found out that all of their barrels except the stainless are chrome lined. I know chrome has better durability is easier to clean but is slightly less accurate. So what are the advantages of owning a SS hbar and why does bushmaster charge more for it?

I live in a high humidity area, and I can tell you, for corrosian resistance stainless is superior!  I own AR's with all three types... stainless (3 Olys), chromemoly unlined (2 DPMS, 1 J&T upper), and an Armalite with chrome-lined chromemoly barrel.  Your SS HBAR barrel is a match grade barrel, and capable of very good accuracy.

Some say the chrome bore will not be as accurate, but in my experience, there is no loss of "practical accuracy".  You won't notice.  In that respect, there is no real disadvantage to chrome-lined.

Some say the chrome bore is easier to clean.  If so, so what?  I have no particular problem cleaning my unlined bores and chambers.

Any advantage of durability with the chrome lining would only come after many 10's of thousands of rounds.  And how rapidly (heat buildup) a rifle is fired is more of a determination of barrel life than the chrome lining.  A chrome chamber MIGHT be better when fed a steady diet of steel cased Wolf ammo.

I don't see that you have a problem... go shoot it and enjoy it.

Also read this thread:

http://www.ar15.com/forums/topic.html?b=3&f=118&t=159186
"AR Discussions  •  Chromed-lined...Advantages???"

Agcsy

Nice avatar!

Your SS barrel leans toward more of a precision rifle.  Of course, that depends on more than just what the barrel is made of, but you get the idea.  SS barrels will be a little more difficult to clean, but nothing that will kill you.  Judging you by your avatar, you have spent some time with an A2, you will find that your SS barrel takes a little more time to clean.

If you are looking to do long range shooting, you should find that your SS barrel is suited a bit better, espcially if you are using optics.  Many people talk about how SS is much more accurate than chrome, but the truth is that most rifles are more accurate than the shooter (chrome or SS).  Lots of people post about how they are shooting 1/2 moa with open iron sights at 100 yards.  Most are flat out liars, the handfull that aren't probably had a real good day.

Either way, you have a good rifle.  Take it out and enjoy it.  Chances are that you won't find much of a difference between the way the two barrels shoot.  Something like the way the two triggers feel will probably make more of a difference.

Stickman, I think that most of the reputation for accuracy for stainless barrels comes from the fact that most of the bull target barrels are stainless.  Some of this has to do with the machining characteristics of the material for the manufacturer.  But from the shooting end of things, the heavy bull contour has a lot to do with it.  So it is not really a fair comparison of a standard chrome lined or chromemoly barrel to a stainless bull target barrel.  

Comparing my 16" Oly carbine heavy SS barreled upper  to a similar similar contour 16" chrome moly DPMS barrel, they are of the same approximate accuracy.