recovered for the Congo early 20th century.

 

a table of Gauge and Calibre

A table showing the various gauge sizes with weights. The bores marked ^* are found in punt guns and rare weapons only. The .410 bore and 23mm caliber are exceptions; they are actual bore sizes, not gauges. If the .410 and 23mm were measured traditionally, they would be 67.62 gauge and 6.278 gauge, respectively.

 

Gauge (Bore)	Diameter		Weight of unalloyed (pure) lead ball
	(mm)	(in)	grams	ounces	grains
AA*	101.60	4.000	6225.52	219.6	96,080
A½*	76.20	3.000	2626.39	92.64	40,530
0.25*	67.34	2.651	1814.36	64.000	28,000
0.5*	53.45	2.103	907.18	32.000	14,000
A*	50.80	2.000	778.19	27.45	12,010
0.75*	46.70	1.838	604.80	21.336	9328
1*	42.42	1.669	453.59	16.000	7000
B½*	38.10	1.500	328.3	11.58	5066
1.5*	37.05	1.459	302.39	10.667	4667
2*	33.67	1.326	226.80	8.000	3500
3*	29.41	1.158	151.20	5.333	2333
4*	26.72	1.052	113.40	4.000	1750
B*	25.40	1.000	97.27	3.43	1501
5*	24.80	.976	90.72	3.200	1400
6*	23.35	.919	75.60	2.667	1166
6.278	23.00	.906	72.26	2.549	1114
7*	22.18	.873	64.80	2.286	1000
8	21.21	.835	56.70	2.000	875
9*	20.39	.803	50.40	1.778	778
10	19.69	.775	45.36	1.600	700
11/C½*	19.05	.750	41.24	1.454	636
12	18.53	.729	37.80	1.333	583
13*	18.04	.710	34.89	1.231	538
14*	17.60	.693	32.40	1.143	500
15*	17.21	.677	30.24	1.067	467
16	16.83	.663	28.35	1.000	438
17*	16.50	.650	26.68	0.941	412
18*	16.19	.637	25.20	0.889	389
20	15.63	.615	22.68	0.800	350
22*	15.13	.596	20.62	0.728	319
24	14.70	.579	18.90	0.667	292
26*	14.31	.564	17.44	0.615	269
28	13.97	.550	16.20	0.571	250
32	13.36	.526	14.17	0.500	219
36	12.85	.506	12.59	0.444	194
C*	12.70	.500	12.16	0.429	188
40	12.40	.488	11.34	0.400	175
67.62	10.41	.410	6.71	0.237	104