In a recent thread (which I can't find right now) a member brought up a black oxide coating for stainless steel.   It is made by Caswell, Inc.  Works like cold blue only for stainless.  I ordered a bottle and it came today.  I blued the exposed part of the stainless barrel on my RRA midlength.  The stuff works great, deep blue-black color, no streaking, well worth a look if you don't like the look of bare stainless barrels.

Phil