That is just polished bluing. The only finish that will give you that look is just that - high polished steel followed by hot caustic bluing.
There are certain PVD finishes that will give you the same gloss, but not the same color. The closest PVD finish I've seen to conventional bluing to date is a brilliant bright blue rather than blue-black. You can get glossy black and various shades of glossy gray in PVD type finishes, but none look like conventional gun blue. Some vendors can get a somewhat glossy finish with DLC, but not quite to the level of a polished blue finish, and DLC coatings are black or dark gray.