Choke and its effectiveness are very much affected by your choice of cartridge. In fact, when choke was first used in shotguns, it actually resulted in worse patterns. Lead is a very soft metal quite prone to deformity. As the shot travels down the barrel at great speed and high pressure, it is inevitable that there will be some damage to its round shape. The degree of this damage relates directly to pattern quality. The more deformity, the poorer the pattern.

Much of this shot damage was prevented by the introduction of antimony into lead shot to increase its hardness. In addition to shot hardness, other components of the shotshell also affect its patterning performance.

The modern shotshell cartridge is, in effect, like the plunger or piston in a bicycle pump. The primer being struck ignites the powder that, combined with the case and crimp, creates sufficient pressure to propel the shot charge along and out the barrel. The wad must be capable of protecting the shot charge from the heat of powder combustion as well as barrel contact while at the same time acting as a piston and seal to make best use of the pressure generated. The shot must be of sufficient hardness to resist deforming while being driven down the barrel.

Wads are either felt, fiber, or plastic, the first two often being chosen for environmental reasons. There can be no argument that the plastic wad is superior, its shot cup protecting the pellets on their journey down the barrel.

Shot Size

The main shot sizes used for clays include No. 9s, 8s, and 7 1/2s. The larger the number the smaller the diameter of individual pellets--and the less energy per pellet. If you shoot 7/25, you have bigger shot and more striking power but fewer pellets than in an equivalent load of 8s. A simple rule of thumb is, out to 35 yards, stick to 8s; past that, 7 1/2s are best. Some shooters favor smaller 9s for wider, more dense patterns at really close targets.

Recoil

In recent articles, we have mentioned recoil, and the shotshell, aside from the weight of the gun, is a big factor in recoil control. You should take this into consideration when making your personal choice of shell. Excessive recoil is both fatigue inducing and the cause of many second-barrel misses.

Speed And Lead

The difference in lead required for a 40-yard target between the average and the fastest cartridge is but a few inches. Surely it is better to find a favorite cartridge and stick with it than continually experimenting with the rocket science of velocity's small effect on lead.

Chris Batha is the senior instructor and gun fitter for London Gunmakers E.J. Churchill. He has over 30 years experience in competitive clays shooting and wingshooting worldwide, has an international reputation as a shooting instructor, and has written extensively on all aspects of shotguns and their use. Batha is a former director of the British Clay Pigeon Shooting Association, with formal qualifications from a variety of other bodies, including the British Association of Shooting and Conservation, British City and Guilds, and National Association of Sports Coaches. He offers shooting instruction, gun fitting, and course design throughout the US.

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