"all service arms had a dull, usually brown, fire-'blued' finish ... never "bright"!"

Well, I used to think so too, but was proved wrong. I wondered why, when producing large quantities of muskets, gunmakers were required to brown or otherwise protect the steel when skipping this step would speed production and cut costs.

Coloring -- browning, bluing -- is a controlled rusting done to protect the surface of the steel. Historically it has been done by several methods, such as soaking a gun barrel in a solution of sal ammoniac (ammonium chloride), boiling it in logwood, or treating it with a nitric acid solution. Bluing, as is found on modern firearms, dates from (roughly) the 19th century.

So I visited various museums, including the Smithsonian's Museum of American History, the museum at Aberdeen Proving Grounds (Maryland), Colonial Williamsburg and others. I found that quite a few military guns -- rifles, muskets and pistols -- were left "in the white." One example is the Charleville musket. Matchlocks with their metal "in the white" can be seen in the Landeszeughaus Graz in Austria. There should also be examples in the Tower armouries and Leeds in the UK.

Another reason -- other than cost and speed of manufacture -- can be found in the massed formations used in warfare. A body of soldiers with the sun glinting off muskets, bayonets and swords is more intimidating. Remember, mass bodies of troops were the rule as recently as WWI.

Besides, I always assumed that the raparree kept his rifle "bright" because he kept it clean and ready for use. That is, the bore was bright.

(I make black powder firearms as a hobby, and hope to take it up again when I get the space to do it. It'd be really hard to do in the condo I'm currently living in.)