Copper Based Alloys do not exist within the DFARS requirements
DFARS (Defense Federal Acquisition Regulation Supplement)
How does this apply to bronze?
Excerpt from DFARS 252.225-7009
Q9. What is the definition of “Specialty Metals”?
A9. The definition of specialty metals is contained in DFARS 252.225-7008:
With a maximum alloy content exceeding one or more of the following limits: manganese, 1.65 percent; silicon, 0.60 percent; or copper, 0.60 percent; or containing more than 0.25 percent of any of the following elements: aluminum, chromium, cobalt, columbium, molybdenum, nickel, titanium, tungsten or vanadium
2. Metal Alloys Consisting of:
Nickel or iron-nickel alloys that contain a total of alloying metals other than nickel and iron in excess of 10 percent; or Cobalt alloys that contain a total of alloying metals other than cobalt and iron in excess of 10 percent
3. Titanium and titanium alloys
4. Zirconium and zirconium base alloys