What are the functional differences between the plain chromoly, the chrome lined, and the stainless?  I know some guys go with no chrome to maximize accuracy but they don't last as long or clean up as easily.  how does stainless compare to the two?  are there differences between manufacturers as far as heat treat, hardness etc..  ?  

TIA

Quoted: What are the functional differences between the plain chromoly, the chrome lined, and the stainless?  I know some guys go with no chrome to maximize accuracy but they don't last as long or clean up as easily.  how does stainless compare to the two?  are there differences between manufacturers as far as heat treat, hardness etc..  ?   TIA

From what I understand:
Chrome moly - Your standard run of the mill barrel. Good enough for most things a person will do unless they are into target shooting.

Chrome lined - A chrome-moly barrel with a chrome-lined bore. Some say the chrome lining makes the rifle less accurate, others say the effect is negligable. The big plus about a chrome lined barrel is longevity. The barrel life on a chrome lined barrel is significantly longer than just a plain chrome moly barrel. Plus, cleaning is simplified, and there is no barrel break in for a C-L'ed barrel (if you believe in that sort of thing).

Stainless Steel - The most accurate of the above choices. If you are going to buy/build a competition/varmint/long range platform, this is the way to go.

As far as what companies do certain things, I believe Bushmaster and I believe Colt uses 4150 steel for their barrels (which I think is better. I'm no metallurgist.), while all the other companies use 4140 on theirs.

cool, so is there any reason to *not* go stainless, other than weight?

Price and not everybody likes their barrels shiny so you might need to coat it/paint it.