“Armory Bright” metal finishes…

[John Spartan]

Own several muzzleloaders with Armory Bright finishes on the barrels.
Seems I have always lived in a humid environment and have been around for some decades but I’m no metal expert of metallurgist.
Why doesn’t the barrel or “bright metal” on a muzzleloader rust easily? Or will it if given half a chance?
I should note for the OCD types maintenance on these weapons is almost a fun hobby on its own so I think I take pretty darn good care of them but have seen other types of bare metal literally show rust in a several hours.
Something about the finish resisting rust? Metal type? Or just lucky I have the time to keep up on them?

 

[BruceHH]

I have a theory - "with no proof what so ever" - that many firearms built back in the day did not have any type of finish applied to the metal. I speculate that it was in the 1800's before firearms started (rountinely) getting browned (then later blued) when first built. I think the rust brown we associate with these firearms came from use outdoors and general handling. The finer the metal finish and the more it was maintained - the less browning of the parts would occur. Highly polished metal is less likely to rust than file finished metal.

 

[John Spartan]

Your theory makes much sense.

 

[longcruise]

Why doesn’t the barrel or “bright metal” on a muzzleloader rust easily?

I think it's related to the amount of carbon in the steel. High carbon steel will rust more readily. I like the in the white look also.

Are these originals or replicas.

 

[rchas]

Any texture on a steel surface will rust more quickly, even microscopic texture. You effectively have more surface area exposed to the elements and the texture itself traps moisture. Polishing removes texture, and reduces surface area. It will still rust, but not as quickly, and you won't have corrosion trapped in the texture making the steel easier to keep corrosion free.

Charcoal bluing and "in the white" were the two most common early steel finishes for firearms. Natural browning through use and handling occurred often. Chemical browning and rust bluing started maybe late 1700's into the early 1800's and became more popular.

 

[John Spartan]

These are military replicas from the late 1700’s/early 1800’s and yes. I like the armory bright also.

 

[longcruise]

These are military replicas from the late 1700’s/early 1800’s and yes. I like the armory bright also.

Those probably have a pretty high polish. Note @rchas remarks above.

I haven't polished my in the white enough and it takes more maintenance.

 

[HighUintas]

I was wondering about this because I plan to do an armory bright finish, but a slightly darkened (not necessarily aged) with brass black that is then rubbed back. From what I understand, the brass black creates a black oxide layer on the steel. So I would assume that when I do this finish, I may not have to oil those surfaces as often to prevent other rust from forming.

Has anyone done this and experienced what I'm theorizing compared to just leaving the steel completely bright and having to do more preventative maintenance?