Wingshooting Wisdom 102: Choke Constriction Choices by Bill Hanus Bill Hanus HELP! HELP! You¹re choking meeeeeeeee... Back when the world was young, shotgun shells were loaded with chilled shot, which deformed easily so that even though a gun might be "necked down like a rifle" it still threw a pattern larger than what we understand "Full" choke to be today. And because small gauge loads exposed a greater percentage of their pellets to this barrel "scrubbing" effect they were always considered (with good cause) to be more "challenging" to shoot. Today’s shotgun shells are an entirely different proposition. The plastic wad, which came into popular use in the 1950s, all but eliminates the problem of lead shot being abraded as it travels along the barrel walls and through forcing cones and chokes. This greater efficiency along with harder shot meant more pellets in the target area and patterns got smaller. And that’s the problem. Your patterns got smaller, but the birds didn’t get bigger. Screw-in chokes A popular bit of fiction found on most shotguns sold in the U.S. today. Screw-in chokes aren’t the answers either, since most choke constriction standards were established before plastic wads came into general use. Also, the manner in which screw-in chokes are designed -- they almost always shoot tighter than advertised. Most shooters end up putting in the Cylinder and Improved Cylinder tubes and leaving them that way. Several manufacturers offer a screw-in choke tube described as a "Spreader" tube, promising a larger pattern than Cylinder. These are usually offered only in 12 gauge for sporting clays shooters, but well worth investigating for field use. As a practical matter, today’s modern ammunition will deliver a 15-inch pattern from a Full choke at 20 yards vs. a 33-inch pattern from a true Cylinder bore at the same distance. The enormity of the tighter choke handicap becomes apparent when we work the numbers. Using the high school formula for the area of a circle: (A = 1/4 r ²) we can conclude that a Cylinder bore which boasts a 33-inch pattern, covering a total of 855 square inches, or 5.9 square feet. The 15-inch Full choke pattern covers 177 square inches, or 1.2 square feet. It is the same size patterns for all gauges, only the density varies by gauge and shot size. Relative Choke Pattern Sizes vs. Cylinder Bore Choke Efficiency:     Cylinder-100%     Skeet #1-83%     Improved Cylinder-62%     Skeet #2-47%     Modified-33%     Full-21% If you conclude that you’re five times more likely to take a 20-yard bird with a Cylinder bore than with a Full choke, and three times more likely than with a Modified choke. Then you will understand why so many of those early shotguns that came from the factory "necked" down like a rifle, were permanently cured of this evil by a visit to the tool shed. Where the chokes were surgically removed along with several inches off the muzzle end by the judicious use of what we know today as a hacksaw. Pellets go just as far and just as fast from a Cylinder bored gun as a Full choked one. Distances and velocities in shotgunning are, after all, functions of load and shot size. It’s been estimated that over 95% of all upland game birds are shot at distances of less that 25 yards. But we all know that guys working behind good dogs are offered lots of 18 and 20-yard opportunities for which Cylinder, Skeet and Improved Cylinder chokes --combined with #8-1/2 and #9 pellet sizes -- provide the best possibly game-taking opportunities. The magic formula is: Open chokes + Small shot size = More Birds