I just wondered why most heavy barrels or varmint barrels are stainless? Are they usually more accurate or something? I would love to have a varmint or heavy barrel that is blued but I cant afford a bushmaster varminter right now.

It partly has to do with the machining characteristics of the steel, and the rifling method.  Read about barrels at the http://www.olyarms.com/usa.html site.  It works in frames, can't give you a direct link.

Click FAQ's on the left.

Scroll down to this question:  "Q: What barrel is on my Oly firearm, or is the barrel on my gun made by OlyArms?" and in the answer click the word "this".

My Oly SS barrels, including my Oly Ultramatch bbl, have their "black oxide" coating that is dead flat black.  No shine.