GunSpec

Material densities

The density of every material a mass check reads, each quoted from the page that states it.

Every mass check in the catalogue rests on one relation: mass is density times volume. A cartridge's case is brass of a known density, a pistol's frame is steel or polymer, a bullet's core is lead. The registry holds each material's density with the page that states it, and the checks read it from there.

m=ρV
1g/cm3=1mg/mm3=1000kg/m3
mpart=φVboxρmaterial

where

ρ
the material's density, from the registry
V
the volume the material fills
φ
the fill fraction: the share of the bounding box the material fills (a steel pistol about 13%)

A density enters the registry only with a page that states it, quoted in the page's own words, and the materials check reads every page again each run. A figure for a class of material (stainless steel) covers its grades with a range (304, 416 and 17-4 PH run from 7.7 to 8.0 g/cm³), and the checks allow for it.

Each material also carries what it is made of: its elements by mass for its typical grade, as the standard or datasheet states them, with the base metal marked balance. The materials check reads those pages again too.

Carbon and alloy steel: the quoted density should fall in the range the registry declares

Answer: 7.85 g/cm³ lies inside 7.75 to 7.9, so the source and the range agree.

MaterialDensityComposition
Leadpure, antimony-hardenedbullet-core, bullet
11.348g/cm³10.9 to 11.35
  • 82PbLead100%
By mass, pure
Copperpurebullet, bullet-jacket
8.935g/cm³8.9 to 8.96
  • 29CuCopper100%
By mass, pure
BronzeC93200frame, receiver
8.8g/cm³8.7 to 8.9
  • 29CuCopper81–85%
  • 82PbLead6–8%
  • 50SnTin6.3–7.5%
  • 30ZnZinc2–4%
By mass, UNS C93200
Gilding metalUNS C21000 (95/5)bullet-jacket
8.8g/cm³8.75 to 8.86
  • 29CuCopper94–96%
  • 30ZnZinc3.7–6%
By mass, UNS C21000
Cartridge brassUNS C26000 (70/30)case, receiver
8.53g/cm³8.5 to 8.55
  • 29CuCopper68.5–71.5%
  • 30ZnZinc28.5%
  • 82PbLead≤ 0.07%
  • 26FeIron≤ 0.05%
By mass, UNS C26000
Nickel silver (German silver)UNS C75200 (65-18)frame, grip
8.5g/cm³8.5 to 8.5
  • 29CuCopper63.5–66.5%
  • 30ZnZinc12.7–20%
  • 28NiNickel16.5–19.5%
  • 25MnManganese≤ 0.5%
By mass, UNS C75200
Stainless steel304, 416, 17-4 PHframe, slide, barrel, receiver, attachment
7.9g/cm³7.7 to 8
  • 26FeIronbalance
  • 24CrChromium18–20%
  • 28NiNickel8–11%
  • 25MnManganese≤ 2%
  • 14SiSilicon≤ 1%
  • 6CCarbon≤ 0.08%
By mass, 304
Ironwrought, castframe, barrel, receiver
7.874g/cm³7 to 7.874
  • 26FeIron100%
By mass, pure
Carbon and alloy steelAISI 4140, AISI 4150, 1018, chrome-molyframe, slide, barrel, receiver, magazine, attachment
7.85g/cm³7.75 to 7.9
  • 26FeIronbalance
  • 24CrChromium0.8–1.1%
  • 25MnManganese0.75–1%
  • 6CCarbon0.38–0.43%
  • 14SiSilicon0.15–0.3%
  • 42MoMolybdenum0.15–0.25%
By mass, AISI 4140
Zinc alloy (Zamak)Zamak 3frame, slide
6.6g/cm³6.6 to 6.7
  • 30ZnZincbalance
  • 13AlAluminium3.9–4.3%
  • 29CuCopper≤ 0.1%
  • 12MgMagnesium0.025–0.05%
By mass, Zamak 3 (ASTM B240 ingot)
Titanium alloyTi-6Al-4V (grade 5)frame, slide, barrel, attachment
4.43g/cm³4.42 to 4.5
  • 22TiTitaniumbalance
  • 13AlAluminium5.5–6.75%
  • 23VVanadium3.5–4.5%
By mass, Ti-6Al-4V
Aluminium alloy6061-T6, 7075-T6frame, receiver, slide, stock, attachment
2.75g/cm³2.7 to 2.81
  • 13AlAluminium95.85–98.56%
  • 12MgMagnesium0.8–1.2%
  • 14SiSilicon0.4–0.8%
  • 26FeIron≤ 0.7%
  • 29CuCopper0.15–0.4%
  • 24CrChromium0.04–0.35%
By mass, 6061
1.85g/cm³1.7 to 2
Glass-fibre composite (fibreglass, G-10)G-10 / FR-4, E-glass fabric in epoxystock, grip, frame
1.85g/cm³1.5 to 2.5
1.85g/cm³1.8 to 1.9
Magnesium alloycast alloysframe, receiver
1.8g/cm³1.8 to 1.8
Carbon fibre compositestandard-modulus fabric in epoxy, M55 unidirectionalstock, frame, barrel, attachment
1.6g/cm³1.6 to 1.65
Glass-filled nylon (polymer)PA66 GF30frame, stock, magazine, attachment
1.36g/cm³1.34 to 1.48
  • (C12H22N2O2)nNylon 66balance
  • Glass fibre30%
By mass, PA66 GF30
Bakelite (phenolic)phenol formaldehydestock, grip
1.3g/cm³1.3 to 1.36
1.15g/cm³1.1 to 1.2
  • (C5H8)nNatural rubberbalance
  • Sulfur and linseed oil25–80%
By mass, ebonite
Nylon 66 (unfilled)PA66, Zytel 101frame, stock
1.14g/cm³1.13 to 1.15
  • (C12H22N2O2)nNylon 66100%
By mass, PA66
Rubber (soft)soft commercial, pure gumstock, grip
1.1g/cm³0.91 to 1.1
0.955g/cm³0.955 to 0.955
  • 6CCarbon50%
  • 8OOxygen42%
  • 1HHydrogen6%
  • 7NNitrogen1%
By mass, wood in generalThe elemental make-up of wood, which varies little between species; the source gives it for wood, not for this species.
Leatherdrystock, grip
0.86g/cm³0.86 to 0.86
0.855g/cm³0.855 to 1.095
  • 6CCarbon50%
  • 8OOxygen42%
  • 1HHydrogen6%
  • 7NNitrogen1%
By mass, wood in generalThe elemental make-up of wood, which varies little between species; the source gives it for wood, not for this species.
0.71g/cm³0.65 to 0.75
  • 6CCarbon50%
  • 8OOxygen42%
  • 1HHydrogen6%
  • 7NNitrogen1%
By mass, wood in generalThe elemental make-up of wood, which varies little between species; the source gives it for wood, not for this species.
0.705g/cm³0.705 to 0.705
  • 6CCarbon50%
  • 8OOxygen42%
  • 1HHydrogen6%
  • 7NNitrogen1%
By mass, wood in generalThe elemental make-up of wood, which varies little between species; the source gives it for wood, not for this species.
0.69g/cm³0.69 to 0.69
  • 6CCarbon50%
  • 8OOxygen42%
  • 1HHydrogen6%
  • 7NNitrogen1%
By mass, wood in generalThe elemental make-up of wood, which varies little between species; the source gives it for wood, not for this species.
0.61g/cm³0.55 to 0.7
  • 6CCarbon50%
  • 8OOxygen42%
  • 1HHydrogen6%
  • 7NNitrogen1%
By mass, wood in generalThe elemental make-up of wood, which varies little between species; the source gives it for wood, not for this species.

Each material also lists the catalogue values it covers (steel, carbon_steel, chromoly_steel and the rest are carbon steel), so a record's frame material finds its density whatever it is called.