You can blue a carbon action with a stainless barrel in a standard blueing tanks. The stainless barrel will not blue, may be a slight shade darker but will cause no harm to the action or contaminate the tank. You have to use special stainless blueing salts in a separate tank to blue stainless, but you can blue stainless. I believe Winchester did it with the .264 and Remington at first with the 7mm mags.
