The 4 bore is a gun whose time has passed, but it seems to hang on. Never manufactured in great numbers, it is still being made today. While Canada and the United States generally forbid hunting with the big gun, the British Isles have no such restrictions, the English hunt geese with them to this day. In the old days the 4 bore was a market hunters tool, either in the form of a punt gun or a shoulder fired arm. Sporting hunters also used the gauge for the largest African game, using round lead balls instead of shot. Guns built for African game are constructed more like rifles, with shorter, stronger barrels equipped with sights. Some 4 bore rifles were equipped with slow (1 in 100) twist rifling. Fowling pieces had barrels ranging from 34 to 46 inches in length. A punt gun barrel could easily be 60 inches long.
The gauge is as old as the shotgun itself, appearing about the time the shotgun differentiated itself from the musket (late 1700's). In those days a man could have a gun made with any bore diameter he wished. Since they were all muzzle loaders, there was little need to standardize on any particular size. Guns larger than 4 bore were almost exclusively punt guns, but I know of at least one 2 bore made to be fired from the shoulder. A shoulder fired 4 bore gun will typically weigh between 15 and 20 lbs.
After the appearance of the breech loader and shotshells bore sizes became more standardized, but a funny thing happened - the 4 bore shrank. While a quarter pound ball of pure lead is just a hair over 1 inch in diameter (true 4 gauge) the breech loader guns were / are built with a bore diameter of between 0.935 and 0.985 inches. The muzzle loaders are most often the true 4 gauge. For this reason, the big tubes are most often referred to as 4 bore, rather than 4 gauge. The 2 bore is in the same boat, really being only larger than a 4 bore and not a 2 gauge in the true sense.
With any older 4 bore gun you must determine the chamber type before shooting. Chambers were made for thin or thick walled brass shells, and for paper shells. Shell lengths varied as well, the "standard" length today is 4 inches. Obtaining shells is dependent on which chamber you have, but you could have a machinist turn you a couple of brass hulls if nothing else. Suppliers of cannon and yacht racing signals sell 4 bore blanks - 25 of them cost $779 before shipping.
Here are two links to currently made 4 bores. The TOZ-123 is probably the least expensive new gun available, the Australian made Century Arms gun has both rifle and shotgun barrels available. (bear defense anyone?)
http://www.tulatoz.ru/en/toz123.html
http://www.centuryarms.com.au/docs/4bore.html
Use Google and search for "4 bore" and gun, and you will find several for sale, most with pictures. Many are single barreled guns, but there are a few doubles as well. Good luck with your search, these are fascinating pieces to research.
Sharptail
