How rare is a Kentucky rifle with a brass barrel?

[Eric Kettenburg]

There are non-destructive methods involving spectrum analysis that can give you an exact breakdown, but they are extremely expensive.  Wallace told me a number of years ago that Winterthur had the capability to do it and were able to determine the difference between 18th century brass and 20th century brass alloys.

[Loudy]

Eric,
Thank you.  I forgot to add CHEAP to my list of criteria for the test.   

I guess density testing could be used as a non-destructive and inexpensive way to differentiate between brass and bronze.  In general, bronze is slightly heavier than brass.  Some sort of water displacement method would be needed to determine the volume of metal being testing.  For most pieces of the size you would find on a firearm, you would need an accurate scale that measures out to three or more decimal places.  Of course, this test method wouldn't tell you anything definative regarding the alloy composition.  Also, this test method wouldn't be of any use on a composite iron & brass (or bronze) barrel like the one on the rifle in the earlier photos.  Food for thought. 

Loudy   
       

[Eric Kettenburg]

Bronze might be slightly heavier than brass, but any result may be skewed by the fact that many 17th and 18th century brass alloys were heavily (by modern standards) leaded.

[Pennsylvania Dutchman]

I sold a couple of 55 gal barrels of bronze shavings from my machine shop a few years ago. I gave the scrap dealer a spec sheet for each barrel telling the analysis of the bronze in each barrel. He used a hand held spectrometer and checked each barrel and said they matched the spec sheets exactly. I would think that one could be used for checking the analysis of the material in a gun barrel to see if it was brass or bronze. It will not affect the material that it is reading in any way, so a gun barrel would not be harmed.
Mark

[Mule Brain]

Is this barrel made of brass or bronze? A bronze barrel can be extremely durable. Back in the day they were also pouring bronze for cannon.   My brother owns a foundry, and I supplied the recipe for cannon bronze so we could pour some barrels. The bronze looks like brass, however far tougher!     

[BOB HILL]

I had some brass that I wanted to forge some ladle bowls from. I cut a piece off and took it to work. One of the engineers took it to the machine shop and checked it with a hand held spectrometer to insure it contained no  lead.
Bob