A Question of Chokes

By Chris Batha

Whenever I give clays competitors lessons, it’s guaranteed that they will have questions about chokes and cartridges. There seems to be a widely held belief that there is a magic formula—some combination of the two—that can fix gaps in their skills and guarantee a step up in class or even help win tournaments.

The bottom line is that if you cannot consistently place the shot pattern on a collision course with the target, you are not going to be successful. But knowledge about your gun’s chokes and how cartridges perform with them is certainly going to be helpful when shot and clay come together.

What Is Choke?

To choke shot pellets means to constrict them with a tightening effect before they exit the gun barrel. The walls of a barrel are parallel, with the inside diameter at the muzzle decreasing to accomplish this. The amount of constriction is measured in thousandths of an inch as compared to the diameter of the bore.

Different countries have different terminology for chokes, and this can result in confusion. Designated names and measurements in inches are used, but often there is not much consistency. In general for a 12-gauge (.729" bore), Cylinder describes no constriction in the barrel, Improved Cylinder (quarter-choke) is .010", Modified (half-choke) is .020", Improved Modified (three-quarters-choke) is .030" and Full is .040".

There are also choke constrictions designed for specific disciplines, such as Skeet. Each manufacturer seems to have its own interpretation of what the amount should be, as constrictions can range from .005" to .008".

Further complicating things is that there are spreader, or diffusion, chokes and also back-bored or over-bored barrels, which can mean that choke tubes have different amounts of constriction in different guns. A choke’s effectiveness is strongly influenced by the cartridges used, and the only way to determine how your cartridge-and-choke combination performs is by pattern-testing.

Fixed & Screw-in Chokes

Through the years, manufacturers have tried many choke designs. Conical, swaged conical, cylindrical-conical, recessed, bell, trumpet, retro, parallel and Tula are but a few.

During the 1960s and ’70s in England, it was common practice among sporting clays competitors to carry two guns: a trap model with a good degree of choke and a skeet model with more-open choking. This allowed for choosing the gun that was best choked for the targets being presented.

The refinement of screw chokes at about that time was revolutionary, creating a system where shotguns could have their barrels machined and threaded to accept screw-in tubes of varying constrictions. This allowed for unprecedented versatility, as chokes could be changed to match the targets. Today most guns come with screw-in chokes, and many specialist companies like Briley and Teague will retrofit screw chokes into fixed-choke guns as well as provide custom tubes for factory-threaded barrels.

Choke works because of the difference in diameter from the boring of the barrel, but this also crushes and deforms some of the pellets from the sudden constriction. The deformed pellets are aerodynamically unstable, leading to the discovery that a more gradual taper in the choke constriction results in fewer of them. Today’s specialist-choke suppliers have refined their products to minimize the deformation of shot, and all modern choke tubes have longer parallel sections than the originals.

Trap, Skeet & Sporting

Target guns today fall into three categories: trap, skeet and sporting clays. In trap and skeet the distances and angles of targets thrown are fixed, allowing guns for these disciplines to be regulated accurately, maximizing pattern widths and densities at set distances. Although many are, there is no need for trap and skeet guns to be multi-choked.

Sporting clays, on the other hand, does not have set angles or distances and, with the variety of target sizes, course setters have become quite ingenious in their presentations. It is the variety of shots that makes sporting clays such an interesting and popular sport and requires a more flexibly choked shotgun—hence the popularity of screw-in chokes on sporting courses.

Many experienced shots find that over time they use very few chokes and change them only for either extremely close or far shots. Others like to see their targets reduced to a ball of dust and prefer to use fixed chokes, with both barrels and chokes fine tuned to shoot these patterns. My personal selection is Light Modified in both barrels, but I stick with multi-chokes for the flexibility of close and far targets.

Fixed v. Screw Chokes

I often am asked if screw chokes pattern better than fixed chokes. Much is made of the extra length of longer choke tubes. However, more-experienced barrel and choke experts than me say that it is a combination of the length of the forcing cones from the chambers to the bore, the back-boring of the barrels and the choke taper that combine to create excellent patterns. But I can say that the ease of changing chokes to match target presentations makes screw chokes a first choice for the sporting clays shooter.

There really is no “magic pill” or “secret formula” for becoming a great shot. The only way is through experimentation and practice.