The relationship between gunshot-residue particle size and Boltzmann distribution

Figures & data

Figure 1. Gunshot-residue (GSR) particles of different sizes formed by fragmentation–splitting and external factors. (A, G, H) spherical structure; (B, D) structure formed by merging; (C, F) structure formed by fragmentation; (E, I) irregular structure.

Figure 2. Gunshot-residue (GSR) particle-size measurement (A) and energy dispersive spectroscopy (EDS) spectrum (B).

Table 1. Statistical values for investigated particles with different dimensional properties from five types of ammunition.

	Amount of particles
	Ammunition type (9 mm); mean value $\overline{X}$					Standard deviation					Confidence range
Size of particles (μm)	MKE	Geco	S&B	WIN	LIBRA	MKE	Geco	S&B	WIN	LIBRA	MKE	Geco	S&B	WIN	LIBRA
0–1	131	149	105	93	85	35.7	29.2	17.5	13.3	11.8	23–284	37–279	40–190	28–113	34–136
1–2	54	46	38	33	29	12.0	7.5	5.7	4.8	3.6	2–102	1–65	2–56	12–45	13–44
2–3	30	25	24	20	19	3.1	5.1	4.4	3.2	2.9	16–46	3–56	5–43	5–32	7–31
3–5	19	22	15	12	10	2.8	2.8	2.2	1.8	1.4	7–26	10–34	6–24	3–17	4–14
5–10	15	18	11	9	7	2.2	1.9	1.2	0.9	0.7	5–20	10–26	6–16	4–10	4–10
10–15	8	9	7	5	4	1.7	0.9	0.6	1.7	0.5	1–14	5–14	4–10	1–15	2–6
15–20	6	7	5	4	5	0.9	1.1	0.3	0.8	0.9	2–8	2–12	4–6	3–9	1–8
25–35	4	3	7	4	3	0.4	0.3	0.5	0.5	0.7	2–6	2–4	5–9	2–6	1–5
>35	2	2	6	3	4	0.2	0.3	0.5	0.3	0.5	1–3	1–3	4–8	1–3	2–6

MKE: Turkey production; Geco: German production; S&B: Czech Republic production; WIN: US production; LIBRA: Czech Republic production.

Figure 3. Fit curve of variation of Gunshot-residue (GSR) particle size–particle number values obtained from Geco (A), WIN (B), LIBRA (C), S&B (D), and MKE (E) brand ammunition according to the Boltzmann distribution.