gun metal ?
I often hear the term "gun metal" used ,but I never really got around to asking anyone what it is.Could it be mild steel(1018),copper,brass,aluminum??I would guess that a gun made of any metal at hand could be considered gun metal..I'm sure it's a very old term.
it's a copper alloy bronze-type material, of varying composition, usually mostly copper, as I recall.
I will look it up later if I remember. Should be in Machinery's handbook though.
It is a naval bronze of some type as Oso says.
Got out a "Modern" reference book, American Machinists Handbook, second edition.
It says 91% copper, 9% tin.
Then in Machinery's 15th edition it lists leaded Gun Metal Castings. SAE Standard No.63.
It says, 86-89% copper,9-11% tin, .25%max phoshorus, zinc and other impurities .5%max, and lead 1 to 2.5%.
Not sure what a newer book will say, my 21st machinery's at work.
Another term I've ran into, machinery steel.
If you ever visit any of the Civil War ("War for Southern Independence") battleground parks, such as Shiloh, and see the old artillery pieces with the greenish, copper patina then you're looking at what was called gun metal.
WOW, I thought gunmetal was 4140 or 4150 steel like they use at Sturm Ruger down the road here (and give me the scrap from.)
Had this re-inforced to me by the old description of January and February in New Hampshire as the ...gunmetal color of winter.... Never saw it a green or bronze color, always looked like a steel gray color.
However, i will defer to the knowledgable on this matter, and in fact thank them for helping me know the real facts.
You lucky dog, getting fed scraps like that! Last hunk 'o stainless (.480 Ruger Super Redhawk -10") I got from them cost me $1200. It sure is - grey, heyyyy, it was supposed to be shiney!