Shotgun bore sizes are well known to be determined by how many bore-diameter lead balls weigh one pound. These were 10, 12, 16 and so forth. The diameter of these lead balls was easily calculated to a thousandth of an inch when the general population was still measuring with wooden rulers. In the U.S., these bore sizes were called gauges, probably after the phrase “made to gauge.” The meaning was that new parts were compared to patterns called gauges and rejected if larger or smaller. It made mass production possible.
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Top 16-Gauge Shotguns - Gun Dog
Many bird hunters are giving in to the sub-gauge craze and finding the 16-gauge shotgun to fit all of their needs.
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