By Phil Bourjaily
Although others claim to have invented the shotgun choke sometime in the 1860s, Fred Kimble, a duck hunter from Peoria, Illinois, often gets the credit in the United States. That's appropriate, as waterfowlers have always been obsessed with improving the performance of their shotguns. Modern screw-in chokes give us some of our most important and versatile tools for dialing in a gun's range and shot pattern. With a basic understanding of chokes and loads, today's waterfowlers can tailor their shotguns to any type of shooting.
How Chokes Work
Like a garden hose nozzle that can be tightened down to emit a single stream or opened to a wide spray, chokes compress the shot charge to varying degrees as it passes through the last few inches of the bore. Shot doesn't flow like water, however. Scott Trulock of Trulock Chokes says, “Think of all those balls in the lotto machine bouncing off each other. That's how pellets react when they're squeezed down.” By lengthening choke tubes and the tapers inside them, and by including a parallel section in the choke after the constriction, manufacturers often leave room in the tube to stabilize shot charges before they're blasted out of the muzzle.
Wad-stripper chokes, like those made by Patternmaster, have no constriction. Instead, they have studs that grab the wad, slowing it and helping the shot pellets separate cleanly and without the disruption of being rammed by the wad. Although wad-strippers and conventional chokes seem quite different, they have a lot in common. All chokes slow the wad as it passes through the constricted section, and it's possible that the studs of wad-stripping chokes also constrict the shot charge somewhat.
There are several ways to identify a choke: by thousandths of an inch of constriction, by their traditional names (e.g., improved cylinder, modified, full), or by their purpose (e.g., pass shooting, timber). Regardless of how a choke is marked, you need to test it in your gun, because every gun is different and the choke is only part of the equation. Typically, higher-velocity loads and smaller shot sizes result in more open patterns. Slower loads and big pellets pattern more tightly. Testing your choke with your gun and your hunting loads is the only way to know what it will do in the field.
Choosing a Choke
Ideally, you want your choke and load combination to put 70 to 75 percent of the shot charge into a 30-inch circle at the range you will most often be shooting. A lot more isn't better, because a super-tight pattern doesn't have as much margin for error around the fringes. In general, skeet or improved cylinder work best for hunting in timber or for teal, when you're shooting small shot that can fill an open pattern. Light modified or modified are good choices for shooting over decoys. Improved modified is the best pick for pass shooting. Full chokes can deliver good patterns, especially with smaller shot, but with tight chokes you begin risking damage to the choke and gun by overconstricting hard pellets.
Given the price of an aftermarket tube, it can make sense to buy one choke and vary your patterns by changing ammunition. I'll confess to using light modified, or what used to be called skeet 2, for almost everything. With small shot this choke produces good patterns for doves and teal, size 2 shot tightens it up for mid-range chances at big ducks over decoys, and with BBs I can confidently shoot at any goose out to 40 yards. Slow BBB loads tighten patterns even further if I really want to reach out.
Choke Tube Care
A rusted-in tube is expensive and sometimes impossible to remove without wrecking the choke and maybe even the barrel. At the end of every season and anytime a gun gets wet, take out the tube, dry it, scrub the threads on the barrel and tube, put a dab of grease on the threads, and put the choke tube back in the gun. A little grease, plus elbow grease, costs a lot less than a new or rethreaded barrel.