A choke is a metal tube that screws into the end of a shotgun barrel, designed to constrict the pellets to varying degrees as they leave the barrel, determining the distance that the pellets spread out after leaving the barrel. This amount of spread is called the pattern. Different chokes cause different pattern densities, appropriate for uses ranging from target shooting to different hunting applications.
Improved Cylinder and Skeet Chokes
The two least constrictive chokes commonly used are the skeet and improved cylinder chokes. A skeet choke is typically a cylinder bore, meaning that it provides no or almost no constriction. Improved cylinder provides slightly more constriction than skeet chokes. These chokes are designed to cause pellets to spread faster to hit closer targets such as fast moving clay targets or upland game in dense woods, where you maximum ranges are about 25 yards.
The modified choke is the most popular, and most versatile choke for the 20 gauge shotgun. Modified chokes provide moderate constriction providing pattern densities designed to hit targets at medium ranges of about 15 to 35 yards. A modified choke will serve most needs adequately, from upland bird hunting, to trap and target shooting, to waterfowl hunting. Most shotguns come fitted from the factory with a modified choke, and if you only own one choke, modified is the choke to choose.
The most constrictive of the standard chokes is the full choke. A full choke is designed to provide the tightest pattern, appropriate for long-range shooting situations such as handicap trap and long-range waterfowl hunting. In a 20 gauge, this means distances from 35 to 45 yards.
These are not the only chokes made for a 20 gauge. Some manufacturers offer several different styles of skeet chokes, sometimes referred to as #1 and #2 skeet, with different constrictions. Another choke occasionally seen is improved modified, which provides a constriction somewhere between modified and full chokes. Turkey chokes are another specialty choke, designed to provide an extremely tight pattern at medium to long ranges, allowing a shooter to hit the vital head and neck area of a standing turkey with enough pellets to kill it at standard turkey ranges of 35 to 40 yards. Turkey chokes are sometimes referred to as super full or extra full chokes.
Exceptions and Testing
It's important to note that these choke descriptions are not absolute for all guns and all loads, especially when it comes to shotgun shells containing steel pellets. For example, a given 20 gauge might have a superb pattern at 40 yards while shooting lead #5 shot through a full choke, but that same choke can perform poorly while shooting #1 steel shot at the same range. For this reason, it becomes important to pattern your gun with the choke you expect to use and the type of shells you will be shooting for a given use. It is possible that your 20 gauge has a tighter pattern with a modified choke and #1 steel shot than it does with a full choke and the same load.
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