The Cherrytree Family

 

 

 

Gauge to Caliber Conversion

The size of a round-ball rifle is spoken of as "so many balls to the pound".  A rifle which was gauged, say, eighty balls to the pound, might actually use a ball 81, 82, 83, or 84 to the pound, depending on the thickness of the patch used with it.  Therefore, a nominal size of the bore meant only that of a ball fitting the bare bore, without the patch.  Following are the micrometer measurements of the gauge used by George Schalk, of Pottsville, PA, 1824-1892.  Schalk was one of America's best rifle smiths and a maker of many famous rifles.  He was "a most careful man" hence, his gauge may be considered reliable.

 

"Balls to the pound" (Gauge) Measurement in inches (Caliber)

5

1.15

6

.954

7

.900

8

.861

9

.823

10

.790

11

.760

12

.748

13

.727

14

.708

15

.695

16

.682

17

.665

18

.647

19

.637

20

.628

21

.618

22

.609

23

.601

24

.588

25

.585

26

.575

27

.572

28

.559

29

.549

30

.533

32

.530

34

.519

36

.506

38

.491

40

.485

44

.474

48

.463

52

.453

56

.442

64

.416

70

.400

80

.388

90

.383

100

.364

110

.350

120

.340

130

.332

140

.324

150

.318

160

.310

170

.305

180

.298

190

.292

200

.290

210

.288

220

.284

230

.282

240

.280

250

.278

260

.274

270

.2715

280

.269

 

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