farmers for pest control inside of barns and sheds, as the snake shot will not shoot holes in the roof or walls, or more importantly injure livestock with a ricochet. They are also used for airport and warehouse pest control. Shot shells have also been historically issued to soldiers, to be used in standard issue rifles. The .45-70 "Forager" round, which contained a thin wooden bullet filled with birdshot, was intended for hunting small game to supplement the soldiers' rations. This round in effect made the .45-70 rifle into a small gauge shotgun, capable of killing rabbits, ducks, and other small game. During World War II, the United States military developed the .45 ACP M12 and M15 shot shells cartridges. They were issued to pilots, to be used as foraging ammunition in the event that they were shot down. While they were best used in the M1917 revolvers, the M15 cartridge would actually cycle the semi-automatic M1911 pistols action. Garden guns Garden guns are smooth-bore firearms specifically made to fire .22 caliber snake shot, and are commonly used by gardeners and farmers for pest control. Garden guns are short-range weapons that can do little harm past 15 to 20 yards, and they are quiet when fired with snake shot, compared to a standard ammunition. These guns are especially effective inside of barns and sheds, as the snake shot will not shoot holes in the roof or walls, or more importantly injure livestock with a ricochet. They are also used for pest control at airports, warehouses, stockyards, etc. Shotgun gauge diameter formula The standard definition of shotgun gauge assumes that a pure lead ball is used. The following formulas relate the bore diameter dn (in inches) to the gauge n: For example, the common bore diameter dn = 0.410 inches (.410 bore) is effectively gauge n = 67.6 . Lead free By 1957 the ammo industry had the capability of producing a nontoxic shot, made out of either iron or steel. In 1976 the Fish and Wildlife Service took the first steps toward phasing out lead shot by designating steel-shot-only hunting zones for waterfowl. In the 1970s lead-free shot shell ammunition loaded with steel, bismuth, or tungsten composite pellets instead of more traditional lead-based pellets was introduced and required for Migratory Bird Hunting (Ducks & Geese). Lead shot in waterfowl hunting was banned throughout the United States in 1991. Due to