| The one distinction that earns the shot-gun name, putting some form of choke to the inside of the barrel giving that gun barrel a specific job to do, shoot shot only. Once you put choke inside of a gun barrel you then have determined a specific use for that gun barrel, the purpose of that choke is to shoot shot, hence shotgun.|
Fred Kimble in 1868 heavily promoted the fixed-choke, choke-bore shotgun barrel that would forever separate muskets from shotguns and help revolutionize the shotgun with one of the greatest of all barrel inventions, the shotgun fixed-choke.
Kimble started experimenting with musket barrels left over from the Civil War, as they were heavy and would stand boring. After repeated attempts to get the correct angles inside the bore he finally came up with a 6-bore or 6 gauge that had a .925" bore diameter that would drop birds at 80 yards. This shotgun would shoot #3 shot through a one-inch board at 40 yards.
Kimble began challenging anyone and everyone at live pigeons with his 6-bore, 36-inch barrel, muzzle-loaded shotgun. The inferior guns of Kimble's competitors were no match for Kimble's choke-bored fixed-choke single shot shotgun. He won match after match and soon, everyone wanted a choked shotgun, and Kimble began to procure regulation double guns and bore them to his new shotgun bore dimensions with choke.
Kimble was not the first person to try his hand at putting some form of choke in a barrel, he did however get the choke-bore procedure correct and promoted this idea with his exploits as a shooter.
When a shotshell is fired from a shotgun, the pellets leave the barrel and begin to spread apart. The farther the pellets travel, the greater the spread of the pellets. Choke is the degree of narrowing or constriction measured in thousandths of an inch at the muzzle end of the shotgun barrel that controls the spread of shot pellets.
.035" Constriction = Full Choke.
.020" Constriction = Modified Choke.
.010" Constriction = Improved Cylinder Choke.
.000" Constriction = Cylinder Bore.
The purpose of the shotgun choke is to control shot dispersion. In a fixed choke shotgun the following results can be expected. The full choked shotgun will place all of its shot within a 40 inch circle at 40 yards. The modified choked shotgun will place all of its shot within a 40 inch circle at 35 yards. The improved cylinder choked shotgun will place all of its shot within a 40 inch circle circle at 30 yards. The cylinder bore shotgun will place all of its shot within a 40 inch circle at 25 yards.
Even though all of the shot can be contained within a 40 inch circle with various chokes at various distances only 70% of that shot pattern is effective for use in the field for hunting. In a fixed choke shotgun the following results can be expected.
The Full Choked Shotgun,
The Modified Choked Shotgun,
The Improved Cylinder Choked Shotgun,
The Cylinder Bore Shotgun,