Gene,
The two gents that posted before me put up some good info. Paper cases often had smaller bore diameters than brass case guns of the same gauge. This is why the 4 bore you referred to had a 6 bore barrel. Longer cases certainly existed in the 19th century, that is why the LC inside the diamond proof mark exists, LC stands for long chamber which is anything over 2&1/2" in a 12 bore. The 3" 12 bore cartridge was used in this time frame, not for more powder or shot but more wadding. The 10 bore 2&7/8" cartridge was also being made during the 19th Century. This has been an interesting thread.
Steve

Last edited by SKB; 04/05/21 06:45 AM. Reason: correction
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